refactor

Cargo.lock

@@ -1314,10 +1314,12 @@ name = "concord"
 version = "1.0.2"
 dependencies = [
  "anyhow",
+ "base64 0.22.1",
  "chacha20 0.9.1",
  "data-encoding",
  "hkdf",
  "hmac 0.12.1",
+ "log",
  "nostr",
  "nostr-memory",
  "nostr-sdk",
@@ -9342,6 +9344,7 @@ dependencies = [
  "chat",
  "chat_ui",
  "common",
+ "community",
  "device",
  "gpui-pre",
  "instant",

Cargo.toml

@@ -36,6 +36,7 @@ nostr = { git = "https://github.com/rust-nostr/nostr", features = [ "nip59", "ni
 
 # Crypto (NIP-17 encrypted file messages)
 aes-gcm = "0.10"
+base64 = "0.22"
 sha2 = "0.10"
 data-encoding = "2"
 hkdf = "0.12"

crates/community/src/community.rs

@@ -70,6 +70,13 @@ impl Community {
         &self.state
     }
 
+    pub fn name(&self) -> String {
+        match &self.control.community {
+            Some(metadata) => metadata.name.clone(),
+            None => self.state.id.to_hex(),
+        }
+    }
+
     pub fn control(&self) -> &ControlFold {
         &self.control
     }

crates/community/src/lib.rs

@@ -3,6 +3,7 @@ use std::collections::HashMap;
 use anyhow::Result;
 use concord::CommunityId;
 use concord::cord01::KIND_WRAP;
+pub use concord::cord02::CommunityMetadata;
 use concord::store::CommunityState;
 use gpui::{App, AppContext, Context, Entity, EventEmitter, Global, Subscription, Task};
 use nostr_sdk::prelude::*;
@@ -103,6 +104,38 @@ impl CommunityRegistry {
         self.index.get(id).cloned()
     }
 
+    /// Create a community owned by the current account and begin tracking it.
+    pub fn create(&mut self, metadata: CommunityMetadata, cx: &mut Context<Self>) {
+        let nostr = NostrRegistry::global(cx);
+        let current_user = nostr.read(cx).current_user();
+
+        if current_user.is_none() {
+            cx.emit(CommunityEvent::Error(
+                "cannot create a community without an account".to_owned(),
+            ));
+            return;
+        }
+
+        let signer = nostr.read(cx).signer();
+        let client = nostr.read(cx).client();
+
+        let task =
+            cx.background_spawn(async move { sync::create(&client, &signer, &metadata).await });
+
+        self.tasks.push(cx.spawn(async move |this, cx| {
+            match task.await {
+                Ok(_state) => this.update(cx, |this, cx| this.load(cx))?,
+                Err(error) => {
+                    this.update(cx, |_this, cx| {
+                        cx.emit(CommunityEvent::Error(error.to_string()));
+                    })?;
+                }
+            }
+
+            Ok(())
+        }));
+    }
+
     /// Forget the current account and cancel everything in flight.
     pub fn reset(&mut self, cx: &mut Context<Self>) {
         self.notification_listener = None;
@@ -171,7 +204,9 @@ impl CommunityRegistry {
             self.observers
                 .push(cx.observe(&community, |this, _community, cx| {
                     this.sync_subscriptions(cx);
+                    cx.notify();
                 }));
+
             self.index.insert(id, community.clone());
             self.communities.push(community);
         }
@@ -197,9 +232,10 @@ impl CommunityRegistry {
     /// Re-subscribe every community whose held planes moved.
     fn sync_subscriptions(&mut self, cx: &mut Context<Self>) {
         let nostr = NostrRegistry::global(cx);
-        let client = nostr.read(cx).client();
 
         for community in self.communities.clone() {
+            let client = nostr.read(cx).client();
+
             let (id, key, state) = {
                 let community = community.read(cx);
                 (
@@ -224,9 +260,9 @@ impl CommunityRegistry {
             let subscription = sync::subscription_id(&id);
             let filter = sync::subscription_filter(&planes);
             let relays = key.relays().to_vec();
+
             self.synced.insert(id, key);
 
-            let client = client.clone();
             self.tasks.push(cx.spawn(async move |this, cx| {
                 if let Err(error) = subscribe(&client, &subscription, &relays, filter).await {
                     this.update(cx, |_this, cx| {
@@ -292,6 +328,7 @@ async fn subscribe(
     relays: &[RelayUrl],
     filter: Filter,
 ) -> Result<()> {
+    log::info!("community {id}: subscribing to {relays:?}");
     client.unsubscribe(id).await?;
 
     for url in relays {
@@ -300,9 +337,6 @@ async fn subscribe(
         }
     }
 
-    // Concord wraps share kind 1059 with NIP-59 gift wraps, so an automatic
-    // target sends gossip after the plane authors as if they were DM peers.
-    // The community's own relays are the routing relays, so target them.
     let target = if relays.is_empty() {
         ReqTarget::auto(vec![filter])
     } else {

crates/community/src/sync.rs

@@ -6,15 +6,14 @@ use concord::cord02::list::{CommunityList, KIND_COMMUNITY_LIST};
 use concord::cord02::{self, ControlFold};
 use concord::cord04::AuthorityCitation;
 use concord::cord04::roles::{Permissions, citation_ok};
-use concord::derive::{channel_group_key, control_group_key, guestbook_group_key};
+use concord::derive::{
+    channel_group_key, control_group_key, control_signer_group_key, guestbook_group_key,
+};
 use concord::store::{self, CommunityState};
 use concord::{ChannelId, CommunityId, Epoch, GroupKey};
 use nostr_sdk::prelude::*;
 use state::UniversalSigner;
 
-const SUBSCRIPTION_PREFIX: &str = "concord/";
-const STATE_PREFIX: &str = "concord/";
-
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub enum PlaneKind {
     Control(Epoch),
@@ -75,13 +74,13 @@ pub fn subscription_filter(planes: &[Plane]) -> Filter {
 }
 
 pub fn subscription_id(id: &CommunityId) -> SubscriptionId {
-    SubscriptionId::new(format!("{SUBSCRIPTION_PREFIX}{}", id.to_hex()))
+    SubscriptionId::new(format!("{}{}", store::STATE_PREFIX, id.to_hex()))
 }
 
 pub fn community_of(subscription_id: &SubscriptionId) -> Option<CommunityId> {
     subscription_id
         .as_str()
-        .strip_prefix(SUBSCRIPTION_PREFIX)?
+        .strip_prefix(store::STATE_PREFIX)?
         .parse()
         .ok()
 }
@@ -93,36 +92,42 @@ pub struct Snapshot {
     pub members: BTreeSet<PublicKey>,
 }
 
+/// Mints a community owned by `signer` and persists it locally.
+pub async fn create<S>(
+    client: &Client,
+    signer: &S,
+    metadata: &cord02::CommunityMetadata,
+) -> Result<CommunityState>
+where
+    S: AsyncGetPublicKey + AsyncSignEvent + ?Sized,
+{
+    let at_secs = Timestamp::now().as_secs();
+    let genesis = cord02::genesis(signer, metadata, at_secs).await?;
+    let id = genesis.identity.community_id;
+
+    let read = control_group_key(&genesis.community_root, &id, cord02::ROOT_EPOCH)?;
+    let address = control_signer_group_key(&genesis.control_root, &id, cord02::ROOT_EPOCH)?.pk();
+
+    let mut editions = Vec::with_capacity(genesis.wraps.len());
+
+    for wrap in &genesis.wraps {
+        editions.push(cord02::open_edition(wrap, &read, &address, true)?);
+        client.database().save_event(wrap).await?;
+    }
+
+    let state = CommunityState::from_genesis(&genesis, &editions, at_secs.saturating_mul(1000))?;
+    store::save_state(client, &state).await?;
+
+    Ok(state)
+}
+
 /// Discovers the current account's communities from the local database.
 pub async fn load(
     client: &Client,
     signer: &UniversalSigner,
     self_pk: PublicKey,
 ) -> Result<Vec<CommunityState>> {
-    let filter = Filter::new().kind(Kind::ApplicationSpecificData);
-    let mut newest: BTreeMap<CommunityId, Event> = BTreeMap::new();
-
-    for event in client.database().query(filter).await? {
-        let Some(id) = state_document_of(&event) else {
-            continue;
-        };
-
-        match newest.get(&id) {
-            Some(existing) if existing.created_at >= event.created_at => {}
-            _ => {
-                newest.insert(id, event);
-            }
-        }
-    }
-
-    let mut states = Vec::with_capacity(newest.len());
-
-    for event in newest.into_values() {
-        match serde_json::from_str::<CommunityState>(&event.content) {
-            Ok(state) => states.push(state),
-            Err(error) => log::warn!("ignoring malformed community state {}: {error}", event.id),
-        }
-    }
+    let mut states = store::load_states(client).await?;
 
     if let Some(list) = load_list(client, signer, self_pk).await? {
         states.retain(|state| list.is_live(&state.id));
@@ -131,12 +136,6 @@ pub async fn load(
     Ok(states)
 }
 
-fn state_document_of(event: &Event) -> Option<CommunityId> {
-    let identifier = event.tags.identifier()?;
-    let hex = identifier.strip_prefix(STATE_PREFIX)?;
-    hex.parse().ok()
-}
-
 async fn load_list(
     client: &Client,
     signer: &UniversalSigner,
@@ -151,9 +150,7 @@ async fn load_list(
         return Ok(None);
     };
 
-    let json = signer.nip44_decrypt_async(&self_pk, &event.content).await?;
-
-    Ok(Some(serde_json::from_str(&json)?))
+    Ok(Some(cord02::list::parse_list_event(signer, &event).await?))
 }
 
 /// Rebuilds a community from the wraps already in the local database.
@@ -259,3 +256,115 @@ fn observe(observed: &mut BTreeMap<PublicKey, u64>, author: PublicKey, at_ms: u6
         .and_modify(|seen| *seen = (*seen).max(at_ms))
         .or_insert(at_ms);
 }
+
+#[cfg(test)]
+mod tests {
+    use nostr_memory::MemoryDatabase;
+
+    use super::*;
+
+    fn client() -> Client {
+        ClientBuilder::default()
+            .database(MemoryDatabase::unbounded())
+            .build()
+    }
+
+    fn metadata(name: &str, relay: &str) -> cord02::CommunityMetadata {
+        cord02::CommunityMetadata {
+            name: name.to_owned(),
+            relays: vec![relay.to_owned()],
+            ..cord02::CommunityMetadata::default()
+        }
+    }
+
+    /// What `CommunityRegistry` needs from a created community: a state document
+    /// `load` finds, a control plane the subscription filter actually addresses,
+    /// and a fold that survives an inbound control edit.
+    #[test]
+    fn creating_a_community_persists_a_state_that_subscribes_and_folds() {
+        smol::block_on(async {
+            let client = client();
+            let keys = Keys::generate();
+            let signer = UniversalSigner::new(keys.clone());
+
+            let created = create(&client, &signer, &metadata("coop", "wss://relay.example"))
+                .await
+                .expect("creates");
+
+            let loaded = load(&client, &signer, keys.public_key())
+                .await
+                .expect("loads");
+            assert_eq!(loaded, vec![created.clone()]);
+
+            // The subscription filter must address the genesis wraps, or the registry
+            // would listen to a plane nothing is ever published on.
+            let planes = planes(&created).expect("planes");
+            let wraps = client
+                .database()
+                .query(subscription_filter(&planes))
+                .await
+                .expect("queries");
+            assert_eq!(wraps.len(), created.heads.len());
+            assert!(wraps.iter().all(|wrap| wrap.kind == Kind::from(KIND_WRAP)));
+
+            let snapshot = fold(&client, &created)
+                .await
+                .expect("folds")
+                .expect("a control plane");
+            assert_eq!(snapshot.state.channels.len(), 1);
+            assert_eq!(snapshot.members, BTreeSet::from([keys.public_key()]));
+            assert_eq!(
+                snapshot
+                    .control
+                    .community
+                    .as_ref()
+                    .map(|metadata| metadata.name.as_str()),
+                Some("coop")
+            );
+
+            // An inbound control edit made by the owner folds over the created state.
+            let community_head = created
+                .heads
+                .iter()
+                .find(|head| head.entity == *created.id.as_bytes())
+                .expect("a community head");
+            let writer = cord02::ControlWriter {
+                author: created.owner,
+                read: control_group_key(&created.community_root, &created.id, cord02::ROOT_EPOCH)
+                    .expect("a reading key"),
+                signer: control_signer_group_key(
+                    &created.control_root.expect("a control root"),
+                    &created.id,
+                    cord02::ROOT_EPOCH,
+                )
+                .expect("a signing key"),
+            };
+
+            let (wrap, _) = writer
+                .set_community_metadata(
+                    &keys,
+                    &created.id,
+                    &metadata("coop two", "wss://relay.example"),
+                    Some(community_head),
+                    None,
+                    Timestamp::now().as_secs() + 1,
+                )
+                .await
+                .expect("publishes");
+            client.database().save_event(&wrap).await.expect("saves");
+
+            let updated = fold(&client, &created)
+                .await
+                .expect("folds")
+                .expect("a control plane");
+            assert_eq!(
+                updated
+                    .control
+                    .community
+                    .as_ref()
+                    .map(|metadata| metadata.name.as_str()),
+                Some("coop two")
+            );
+        });
+    }
+}

crates/concord/Cargo.toml

@@ -13,10 +13,12 @@ sha2.workspace = true
 chacha20.workspace = true
 hmac.workspace = true
 data-encoding.workspace = true
+base64.workspace = true
 rand.workspace = true
 serde.workspace = true
 serde_json.workspace = true
 anyhow.workspace = true
+log.workspace = true
 
 [dev-dependencies]
 nostr-memory.workspace = true

crates/concord/src/cords/cord01.rs

@@ -3,8 +3,8 @@ use std::fmt;
 use data_encoding::BASE64;
 use nostr::nips::nip44::v2::{ConversationKey, decrypt_to_bytes, encrypt_to_bytes_with_nonce};
 use nostr_sdk::prelude::{
-    Event, EventBuilder, EventId, FinalizeEvent, Keys, Kind, PublicKey, Tag, Timestamp,
-    UnsignedEvent,
+    AsyncGetPublicKey, AsyncNip44, AsyncSignEvent, Event, EventBuilder, EventId, FinalizeEvent,
+    FinalizeEventAsync, Keys, Kind, PublicKey, Tag, Timestamp, UnsignedEvent,
 };
 
 use crate::derive::GroupKey;
@@ -198,32 +198,52 @@ pub fn open_bytes(conversation: &ConversationKey, content: &str) -> Result<Vec<u
 }
 
 /// A member's own document (the Community List, the Invite List): NIP-44 to self.
-pub fn seal_to_self(keys: &Keys, plaintext: &[u8]) -> Result<String, StreamError> {
-    seal_bytes(
-        &ConversationKey::derive(keys.secret_key(), &keys.public_key())
-            .map_err(|error| StreamError::Encrypt(error.to_string()))?,
-        plaintext,
-    )
+pub async fn seal_to_self<S>(signer: &S, plaintext: &str) -> Result<String, StreamError>
+where
+    S: AsyncGetPublicKey + AsyncNip44 + ?Sized,
+{
+    check_plaintext_cap(plaintext.len())?;
+
+    let address = signer
+        .get_public_key_async()
+        .await
+        .map_err(|error| StreamError::Encrypt(error.to_string()))?;
+
+    signer
+        .nip44_encrypt_async(&address, plaintext)
+        .await
+        .map_err(|error| StreamError::Encrypt(error.to_string()))
 }
 
-pub fn open_to_self(keys: &Keys, content: &str) -> Result<Vec<u8>, StreamError> {
-    open_bytes(
-        &ConversationKey::derive(keys.secret_key(), &keys.public_key())
-            .map_err(|error| StreamError::Decrypt(error.to_string()))?,
-        content,
-    )
+pub async fn open_to_self<S>(signer: &S, content: &str) -> Result<String, StreamError>
+where
+    S: AsyncGetPublicKey + AsyncNip44 + ?Sized,
+{
+    let address = signer
+        .get_public_key_async()
+        .await
+        .map_err(|error| StreamError::Decrypt(error.to_string()))?;
+
+    signer
+        .nip44_decrypt_async(&address, content)
+        .await
+        .map_err(|error| StreamError::Decrypt(error.to_string()))
 }
 
-pub fn build_seal(
+pub async fn build_seal<S>(
     rumor: &UnsignedEvent,
     form: SealForm,
     group: &GroupKey,
-    author: &Keys,
-) -> Result<Event, StreamError> {
+    author: &S,
+) -> Result<Event, StreamError>
+where
+    S: AsyncGetPublicKey + AsyncSignEvent + ?Sized,
+{
     let content = seal_content(rumor, form, group)?;
     EventBuilder::new(Kind::Custom(form.kind()), content)
         .custom_created_at(rumor.created_at)
-        .finalize(author)
+        .finalize_async(author)
+        .await
         .map_err(|error| StreamError::Sign(error.to_string()))
 }
 
@@ -450,7 +470,7 @@ mod tests {
     }
 
     fn sealed(rumor: &UnsignedEvent, form: SealForm, author: &Keys) -> Event {
-        build_seal(rumor, form, &group(0), author).expect("seals")
+        smol::block_on(build_seal(rumor, form, &group(0), author)).expect("seals")
     }
 
     fn wrapped(seal: &Event, kind: u16, at_secs: u64) -> Event {

crates/concord/src/cords/cord02/guestbook.rs

@@ -1,18 +1,16 @@
 use std::cmp::Reverse;
 use std::collections::{BTreeMap, BTreeSet};
-use std::fmt;
 
 use anyhow::Result;
 use data_encoding::HEXLOWER;
 use nostr_sdk::prelude::*;
 
 use crate::cord01::{
-    KIND_WRAP, OpenedStream, SealForm, StreamError, build_rumor_ms, build_seal, open_wrap,
-    wrap_seal,
-};
-use crate::cord04::{
-    AuthorityCitation, TAG_CITATION, canonical_decimal, citation_from, citation_tag,
+    KIND_WRAP, OpenedStream, SealForm, build_rumor_ms, build_seal, open_wrap, wrap_seal,
 };
+use crate::cord04::{AuthorityCitation, canonical_decimal, citation_tag};
+pub use crate::cords::rumor::RumorError as GuestbookError;
+use crate::cords::rumor::{optional_citation, pubkey, required, value};
 use crate::{GroupKey, decode_hex_32};
 
 pub const KIND_JOIN_LEAVE: u16 = 3306;
@@ -29,41 +27,6 @@ const TAG_CONTENT: &str = "content";
 const CONTENT_JOIN: &str = "join";
 const CONTENT_LEAVE: &str = "leave";
 
-#[derive(Debug)]
-pub enum GuestbookError {
-    Stream(StreamError),
-    NotEncryptedSealed,
-    UnknownKind(u16),
-    MissingTag(&'static str),
-    DuplicateTag(&'static str),
-    BadTag(&'static str),
-}
-
-impl fmt::Display for GuestbookError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            GuestbookError::Stream(error) => write!(f, "stream: {error}"),
-            GuestbookError::NotEncryptedSealed => {
-                write!(f, "guestbook rumor must ride an encrypted seal")
-            }
-            GuestbookError::UnknownKind(kind) => {
-                write!(f, "not a guestbook rumor kind: {kind}")
-            }
-            GuestbookError::MissingTag(name) => write!(f, "missing guestbook tag: {name}"),
-            GuestbookError::DuplicateTag(name) => write!(f, "duplicate guestbook tag: {name}"),
-            GuestbookError::BadTag(name) => write!(f, "malformed guestbook tag: {name}"),
-        }
-    }
-}
-
-impl std::error::Error for GuestbookError {}
-
-impl From<StreamError> for GuestbookError {
-    fn from(error: StreamError) -> Self {
-        GuestbookError::Stream(error)
-    }
-}
-
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum GuestbookEntry {
     Join {
@@ -183,18 +146,21 @@ pub fn build_snapshot_chunks(
         .collect()
 }
 
-pub fn seal_rumor(
+pub async fn seal_rumor<S>(
     rumor: &UnsignedEvent,
     group: &GroupKey,
-    author: &Keys,
-) -> Result<(Event, Keys), GuestbookError> {
+    author: &S,
+) -> Result<(Event, Keys), GuestbookError>
+where
+    S: AsyncGetPublicKey + AsyncSignEvent + ?Sized,
+{
     let kind = rumor.kind.as_u16();
 
     if !is_guestbook_kind(kind) {
         return Err(GuestbookError::UnknownKind(kind));
     }
 
-    let seal = build_seal(rumor, SealForm::Encrypted, group, author)?;
+    let seal = build_seal(rumor, SealForm::Encrypted, group, author).await?;
 
     Ok(wrap_seal(&seal, group, KIND_WRAP, rumor.created_at, &[])?)
 }
@@ -466,73 +432,21 @@ fn snapshot_of(rumor: &UnsignedEvent) -> Result<([u8; 32], (u32, u32)), Guestboo
     Ok((snapshot_id, (index, total)))
 }
 
-fn optional_citation(rumor: &UnsignedEvent) -> Result<Option<AuthorityCitation>, GuestbookError> {
-    let Some(fields) = tag(rumor, TAG_CITATION)? else {
-        return Ok(None);
-    };
-
-    citation_from(fields)
-        .map(Some)
-        .ok_or(GuestbookError::BadTag(TAG_CITATION))
-}
-
 fn decimal(raw: &str) -> Result<u32, GuestbookError> {
     canonical_decimal(raw)
         .and_then(|value| u32::try_from(value).ok())
         .ok_or(GuestbookError::BadTag(TAG_SNAP))
 }
 
-fn required<'a>(
-    rumor: &'a UnsignedEvent,
-    name: &'static str,
-) -> Result<&'a [String], GuestbookError> {
-    tag(rumor, name)?.ok_or(GuestbookError::MissingTag(name))
-}
-
 fn tagged_pubkey(rumor: &UnsignedEvent, name: &'static str) -> Result<PublicKey, GuestbookError> {
     pubkey(value(required(rumor, name)?, name)?, name)
 }
 
-fn tag<'a>(
-    rumor: &'a UnsignedEvent,
-    name: &'static str,
-) -> Result<Option<&'a [String]>, GuestbookError> {
-    let mut found: Option<&[String]> = None;
-
-    for candidate in rumor.tags.iter() {
-        let fields = candidate.as_slice();
-
-        if fields.first().map(String::as_str) != Some(name) {
-            continue;
-        }
-
-        if found.is_some() {
-            return Err(GuestbookError::DuplicateTag(name));
-        }
-
-        found = Some(fields);
-    }
-
-    Ok(found)
-}
-
-fn value<'a>(fields: &'a [String], name: &'static str) -> Result<&'a str, GuestbookError> {
-    fields
-        .get(1)
-        .map(String::as_str)
-        .ok_or(GuestbookError::BadTag(name))
-}
-
-fn pubkey(hex: &str, name: &'static str) -> Result<PublicKey, GuestbookError> {
-    let bytes = decode_hex_32(hex).map_err(|_| GuestbookError::BadTag(name))?;
-
-    PublicKey::from_slice(&bytes).map_err(|_| GuestbookError::BadTag(name))
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::cord01::build_rumor_secs;
+    use crate::cord01::{StreamError, build_rumor_secs};
+    use crate::cord04::TAG_CITATION;
     use crate::derive::guestbook_group_key;
     use crate::{CommunityId, Epoch};
 
@@ -556,7 +470,9 @@ mod tests {
     }
 
     fn publish(rumor: &UnsignedEvent, author: &Keys) -> GuestbookRumor {
-        let wrap = seal_rumor(rumor, &group(), author).expect("seals").0;
+        let wrap = smol::block_on(seal_rumor(rumor, &group(), author))
+            .expect("seals")
+            .0;
 
         open(&wrap, &group()).expect("opens").1
     }
@@ -826,7 +742,9 @@ mod tests {
         );
         assert!(matches!(
             open(
-                &seal_rumor(&bad_ms, &group(), &member).expect("seals").0,
+                &smol::block_on(seal_rumor(&bad_ms, &group(), &member))
+                    .expect("seals")
+                    .0,
                 &group()
             ),
             Err(GuestbookError::Stream(StreamError::BadMs))
@@ -835,7 +753,9 @@ mod tests {
         let bad_verb = build_rumor_ms(KIND_JOIN_LEAVE, member.public_key(), "maybe", vec![], AT);
         assert!(matches!(
             open(
-                &seal_rumor(&bad_verb, &group(), &member).expect("seals").0,
+                &smol::block_on(seal_rumor(&bad_verb, &group(), &member))
+                    .expect("seals")
+                    .0,
                 &group()
             ),
             Err(GuestbookError::BadTag(TAG_CONTENT))
@@ -854,7 +774,7 @@ mod tests {
         );
         assert!(matches!(
             open(
-                &seal_rumor(&ambiguous, &group(), &moderator)
+                &smol::block_on(seal_rumor(&ambiguous, &group(), &moderator))
                     .expect("seals")
                     .0,
                 &group()
@@ -876,7 +796,9 @@ mod tests {
             );
             assert!(matches!(
                 open(
-                    &seal_rumor(&rumor, &group(), &moderator).expect("seals").0,
+                    &smol::block_on(seal_rumor(&rumor, &group(), &moderator))
+                        .expect("seals")
+                        .0,
                     &group()
                 ),
                 Err(GuestbookError::BadTag(TAG_SNAP))

crates/concord/src/cords/cord02/list.rs

@@ -1,15 +1,17 @@
-use std::collections::BTreeMap;
 use std::collections::btree_map::Entry;
+use std::collections::{BTreeMap, BTreeSet};
 use std::fmt;
 
+use data_encoding::HEXLOWER;
 use nostr_sdk::prelude::*;
-use serde::{Deserialize, Serialize};
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
 
 use crate::cord01::{self, NIP44_MAX_PLAINTEXT};
 use crate::cord05::{ChannelGrant, CommunityInvite};
-use crate::{CommunityId, Epoch, Extra};
+use crate::utils::{base64_to_hex32, base64url, canonical, hex32_to_base64, union};
+use crate::{ChannelId, CommunityId, Epoch, Extra};
 
-pub const KIND_COMMUNITY_LIST: u16 = 13302;
+pub const KIND_COMMUNITY_LIST: u16 = 33302;
 pub const MAX_MEMBERSHIPS: usize = 50;
 
 #[derive(Debug)]
@@ -17,6 +19,8 @@ pub enum ListError {
     Kind(u16),
     Crypto(String),
     Json(String),
+    Encoding(String),
+    Fragment(String),
     TooManyMemberships(usize),
     Oversize(usize),
 }
@@ -27,6 +31,8 @@ impl fmt::Display for ListError {
             ListError::Kind(kind) => write!(f, "not a community list kind: {kind}"),
             ListError::Crypto(error) => write!(f, "crypto: {error}"),
             ListError::Json(error) => write!(f, "json: {error}"),
+            ListError::Encoding(error) => write!(f, "encoding: {error}"),
+            ListError::Fragment(error) => write!(f, "fragment: {error}"),
             ListError::TooManyMemberships(count) => {
                 write!(
                     f,
@@ -48,55 +54,58 @@ impl From<cord01::StreamError> for ListError {
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct JoinMaterial {
     pub community_id: CommunityId,
     pub owner: PublicKey,
     pub owner_salt: String,
     pub community_root: String,
     pub root_epoch: Epoch,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub control_pk: Option<PublicKey>,
     /// Present only when the holder is staff.
-    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub control_root: Option<String>,
-    #[serde(default, skip_serializing_if = "Vec::is_empty")]
     pub channels: Vec<ChannelGrant>,
-    #[serde(default, skip_serializing_if = "Vec::is_empty")]
     pub relays: Vec<String>,
     pub name: String,
-    #[serde(flatten)]
     pub extra: Extra,
 }
 
-#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct CommunityListEntry {
     pub community_id: CommunityId,
     pub seed: JoinMaterial,
     pub current: JoinMaterial,
     pub added_at: u64,
-    #[serde(flatten)]
     pub extra: Extra,
 }
 
-#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct Tombstone {
     pub community_id: CommunityId,
     pub removed_at: u64,
-    #[serde(flatten)]
     pub extra: Extra,
 }
 
-#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct CommunityList {
-    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    /// How many fragments this List has. Every fragment declares it.
+    pub frags: u64,
     pub entries: Vec<CommunityListEntry>,
-    #[serde(default, skip_serializing_if = "Vec::is_empty")]
     pub tombstones: Vec<Tombstone>,
-    #[serde(flatten)]
     pub extra: Extra,
 }
 
+impl Default for CommunityList {
+    fn default() -> Self {
+        Self {
+            frags: 1,
+            entries: Vec::new(),
+            tombstones: Vec::new(),
+            extra: Extra::default(),
+        }
+    }
+}
+
 impl CommunityList {
     pub fn is_live(&self, community_id: &CommunityId) -> bool {
         let added = self
@@ -115,6 +124,14 @@ impl CommunityList {
         }
     }
 
+    pub fn is_complete<I>(&self, held: I) -> bool
+    where
+        I: IntoIterator<Item = u64>,
+    {
+        let held: BTreeSet<u64> = held.into_iter().collect();
+        (0..self.frags).all(|index| held.contains(&index))
+    }
+
     pub fn fits(&self) -> Result<(), ListError> {
         if self.entries.len() > MAX_MEMBERSHIPS {
             return Err(ListError::TooManyMemberships(self.entries.len()));
@@ -138,7 +155,7 @@ pub fn join_material(invite: &CommunityInvite, control_root: Option<&[u8; 32]>)
         community_root: invite.community_root.clone(),
         root_epoch: invite.root_epoch,
         control_pk: invite.control_pk,
-        control_root: control_root.map(|key| data_encoding::HEXLOWER.encode(key)),
+        control_root: control_root.map(|key| HEXLOWER.encode(key)),
         channels: invite.channels.clone(),
         relays: invite.relays.clone(),
         name: invite.name.clone(),
@@ -149,7 +166,9 @@ pub fn join_material(invite: &CommunityInvite, control_root: Option<&[u8; 32]>)
 pub fn merge(held: CommunityList, incoming: CommunityList) -> CommunityList {
     let mut entries: BTreeMap<CommunityId, CommunityListEntry> = BTreeMap::new();
 
-    for entry in held.entries.into_iter().chain(incoming.entries) {
+    for mut entry in held.entries.into_iter().chain(incoming.entries) {
+        normalize(&mut entry);
+
         match entries.entry(entry.community_id) {
             Entry::Vacant(slot) => {
                 slot.insert(entry);
@@ -177,31 +196,359 @@ pub fn merge(held: CommunityList, incoming: CommunityList) -> CommunityList {
     union(&mut extra, incoming.extra);
 
     CommunityList {
+        frags: held.frags.max(incoming.frags),
         entries: entries.into_values().collect(),
         tombstones: tombstones.into_values().collect(),
         extra,
     }
 }
 
-pub fn build_list_event(keys: &Keys, list: &CommunityList) -> Result<Event, ListError> {
+pub async fn build_list_event<S>(
+    signer: &S,
+    list: &CommunityList,
+    fragment: u64,
+) -> Result<Event, ListError>
+where
+    S: AsyncGetPublicKey + AsyncSignEvent + AsyncNip44 + ?Sized,
+{
     list.fits()?;
 
     let json = serde_json::to_string(list).map_err(json_error)?;
-    let content = cord01::seal_to_self(keys, json.as_bytes())?;
+    let content = cord01::seal_to_self(signer, &json).await?;
 
     EventBuilder::new(Kind::Custom(KIND_COMMUNITY_LIST), content)
-        .finalize(keys)
+        .tag(Tag::identifier(fragment.to_string()))
+        .finalize_async(signer)
+        .await
         .map_err(crypto_error)
 }
 
-pub fn parse_list_event(keys: &Keys, event: &Event) -> Result<CommunityList, ListError> {
+pub async fn parse_list_event<S>(signer: &S, event: &Event) -> Result<CommunityList, ListError>
+where
+    S: AsyncGetPublicKey + AsyncNip44 + ?Sized,
+{
     if event.kind.as_u16() != KIND_COMMUNITY_LIST {
         return Err(ListError::Kind(event.kind.as_u16()));
     }
 
-    let json = cord01::open_to_self(keys, &event.content)?;
+    fragment_index(event)?;
 
-    serde_json::from_slice(&json).map_err(json_error)
+    let json = cord01::open_to_self(signer, &event.content).await?;
+
+    serde_json::from_str(&json).map_err(json_error)
+}
+
+pub fn fragment_index(event: &Event) -> Result<u64, ListError> {
+    let value = event
+        .tags
+        .identifier()
+        .ok_or_else(|| ListError::Fragment("missing d tag".to_owned()))?;
+
+    value
+        .parse()
+        .map_err(|_| ListError::Fragment(format!("d tag is not a fragment index: {value}")))
+}
+
+fn decode_base64(value: &str, field: &str) -> Result<[u8; 32], ListError> {
+    base64url::decode_32(value).map_err(|error| ListError::Encoding(format!("{field}: {error}")))
+}
+
+fn decode_community_id(value: &str) -> Result<CommunityId, ListError> {
+    Ok(CommunityId::from_bytes(decode_base64(
+        value,
+        "community_id",
+    )?))
+}
+
+fn decode_public_key(value: &str, field: &str) -> Result<PublicKey, ListError> {
+    PublicKey::from_slice(&decode_base64(value, field)?)
+        .map_err(|error| ListError::Encoding(format!("{field}: {error}")))
+}
+
+fn encode_hex_32(value: &str, field: &str) -> Result<String, ListError> {
+    hex32_to_base64(value).map_err(|error| ListError::Encoding(format!("{field}: {error}")))
+}
+
+fn decode_hex_32_base64(value: &str, field: &str) -> Result<String, ListError> {
+    base64_to_hex32(value).map_err(|error| ListError::Encoding(format!("{field}: {error}")))
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+struct WireList {
+    #[serde(default = "one_fragment")]
+    frags: u64,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    entries: Vec<WireEntry>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    tombstones: Vec<WireTombstone>,
+    #[serde(flatten)]
+    extra: Extra,
+}
+
+fn one_fragment() -> u64 {
+    1
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+struct WireEntry {
+    community_id: String,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    seed: Option<WireSnapshot>,
+    current: WireSnapshot,
+    added_at: u64,
+    #[serde(flatten)]
+    extra: Extra,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+struct WireTombstone {
+    community_id: String,
+    removed_at: u64,
+    #[serde(flatten)]
+    extra: Extra,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+struct WireSnapshot {
+    owner: String,
+    owner_salt: String,
+    community_root: String,
+    root_epoch: Epoch,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    control_pk: Option<String>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    control_root: Option<String>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    channels: Vec<WireChannel>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    relays: Vec<String>,
+    name: String,
+    #[serde(flatten)]
+    extra: Extra,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+struct WireChannel {
+    id: String,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    key: Option<String>,
+    epoch: Epoch,
+    #[serde(default)]
+    name: String,
+    #[serde(flatten)]
+    extra: Extra,
+}
+
+impl WireList {
+    fn encode(list: &CommunityList) -> Result<Self, ListError> {
+        // §8: a retired entry is not written — the tombstone alone carries the
+        // state, since a membership is live only while an entry outranks its
+        // removal. The entry stays in the in-memory document.
+        let mut entries = Vec::with_capacity(list.entries.len());
+        for entry in &list.entries {
+            if list.is_live(&entry.community_id) {
+                entries.push(WireEntry::encode(entry)?);
+            }
+        }
+
+        let mut tombstones = Vec::with_capacity(list.tombstones.len());
+        for tombstone in &list.tombstones {
+            tombstones.push(WireTombstone::encode(tombstone)?);
+        }
+
+        Ok(Self {
+            frags: list.frags,
+            entries,
+            tombstones,
+            extra: list.extra.clone(),
+        })
+    }
+
+    fn decode(self) -> Result<CommunityList, ListError> {
+        let mut entries = Vec::with_capacity(self.entries.len());
+        for entry in self.entries {
+            entries.push(entry.decode()?);
+        }
+
+        let mut tombstones = Vec::with_capacity(self.tombstones.len());
+        for tombstone in self.tombstones {
+            tombstones.push(tombstone.decode()?);
+        }
+
+        Ok(CommunityList {
+            frags: self.frags.max(1),
+            entries,
+            tombstones,
+            extra: self.extra,
+        })
+    }
+}
+
+impl WireEntry {
+    fn encode(entry: &CommunityListEntry) -> Result<Self, ListError> {
+        let current = WireSnapshot::encode(&entry.current)?;
+
+        let mut seed = entry.seed.clone();
+        normalize_snapshot(&mut seed, &entry.current);
+
+        let seed = if seed == entry.current {
+            None
+        } else {
+            Some(WireSnapshot::encode(&seed)?)
+        };
+
+        Ok(Self {
+            community_id: base64url::encode(entry.community_id.as_bytes()),
+            seed,
+            current,
+            added_at: entry.added_at,
+            extra: entry.extra.clone(),
+        })
+    }
+
+    fn decode(self) -> Result<CommunityListEntry, ListError> {
+        let community_id = decode_community_id(&self.community_id)?;
+        let current = self.current.decode(community_id)?;
+        let seed = match self.seed {
+            Some(seed) => seed.decode(community_id)?,
+            None => current.clone(),
+        };
+
+        let mut entry = CommunityListEntry {
+            community_id,
+            seed,
+            current,
+            added_at: self.added_at,
+            extra: self.extra,
+        };
+        normalize(&mut entry);
+
+        Ok(entry)
+    }
+}
+
+impl WireTombstone {
+    fn encode(tombstone: &Tombstone) -> Result<Self, ListError> {
+        Ok(Self {
+            community_id: base64url::encode(tombstone.community_id.as_bytes()),
+            removed_at: tombstone.removed_at,
+            extra: tombstone.extra.clone(),
+        })
+    }
+
+    fn decode(self) -> Result<Tombstone, ListError> {
+        Ok(Tombstone {
+            community_id: decode_community_id(&self.community_id)?,
+            removed_at: self.removed_at,
+            extra: self.extra,
+        })
+    }
+}
+
+impl WireSnapshot {
+    fn encode(material: &JoinMaterial) -> Result<Self, ListError> {
+        let mut channels = Vec::with_capacity(material.channels.len());
+        for channel in &material.channels {
+            channels.push(WireChannel::encode(channel)?);
+        }
+
+        Ok(Self {
+            owner: base64url::encode(&material.owner.to_bytes()),
+            owner_salt: encode_hex_32(&material.owner_salt, "owner_salt")?,
+            community_root: encode_hex_32(&material.community_root, "community_root")?,
+            root_epoch: material.root_epoch,
+            control_pk: material
+                .control_pk
+                .map(|key| base64url::encode(&key.to_bytes())),
+            control_root: match &material.control_root {
+                Some(root) => Some(encode_hex_32(root, "control_root")?),
+                None => None,
+            },
+            channels,
+            relays: material.relays.clone(),
+            name: material.name.clone(),
+            extra: material.extra.clone(),
+        })
+    }
+
+    fn decode(self, community_id: CommunityId) -> Result<JoinMaterial, ListError> {
+        let mut channels = Vec::with_capacity(self.channels.len());
+        for channel in self.channels {
+            channels.push(channel.decode()?);
+        }
+
+        Ok(JoinMaterial {
+            community_id,
+            owner: decode_public_key(&self.owner, "owner")?,
+            owner_salt: decode_hex_32_base64(&self.owner_salt, "owner_salt")?,
+            community_root: decode_hex_32_base64(&self.community_root, "community_root")?,
+            root_epoch: self.root_epoch,
+            control_pk: match self.control_pk {
+                Some(value) => Some(decode_public_key(&value, "control_pk")?),
+                None => None,
+            },
+            control_root: match self.control_root {
+                Some(value) => Some(decode_hex_32_base64(&value, "control_root")?),
+                None => None,
+            },
+            channels,
+            relays: self.relays,
+            name: self.name,
+            extra: self.extra,
+        })
+    }
+}
+
+impl WireChannel {
+    fn encode(grant: &ChannelGrant) -> Result<Self, ListError> {
+        Ok(Self {
+            id: base64url::encode(grant.id.as_bytes()),
+            key: match &grant.key {
+                Some(key) => Some(encode_hex_32(key, "channel key")?),
+                None => None,
+            },
+            epoch: grant.epoch,
+            name: grant.name.clone(),
+            extra: grant.extra.clone(),
+        })
+    }
+
+    fn decode(self) -> Result<ChannelGrant, ListError> {
+        Ok(ChannelGrant {
+            id: ChannelId::from_bytes(decode_base64(&self.id, "channel id")?),
+            key: match self.key {
+                Some(value) => Some(decode_hex_32_base64(&value, "channel key")?),
+                None => None,
+            },
+            epoch: self.epoch,
+            name: self.name,
+            extra: self.extra,
+        })
+    }
+}
+
+impl Serialize for CommunityList {
+    fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+        WireList::encode(self)
+            .map_err(serde::ser::Error::custom)?
+            .serialize(serializer)
+    }
+}
+
+impl<'de> Deserialize<'de> for CommunityList {
+    fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
+        WireList::deserialize(deserializer)?
+            .decode()
+            .map_err(serde::de::Error::custom)
+    }
+}
+
+impl Serialize for JoinMaterial {
+    fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+        WireSnapshot::encode(self)
+            .map_err(serde::ser::Error::custom)?
+            .serialize(serializer)
+    }
 }
 
 #[derive(Clone, Copy, PartialEq, Eq)]
@@ -215,6 +562,7 @@ fn merge_entry(held: &mut CommunityListEntry, incoming: CommunityListEntry) {
     held.seed = pick(&held.seed, &incoming.seed, Snapshot::Seed).clone();
     held.current = pick(&held.current, &incoming.current, Snapshot::Current).clone();
     union(&mut held.extra, incoming.extra);
+    normalize(held);
 }
 
 fn pick<'a>(
@@ -238,21 +586,26 @@ fn pick<'a>(
     held
 }
 
-pub(crate) fn union(into: &mut Extra, other: Extra) {
-    for (key, value) in other {
-        let replace = match into.get(&key) {
-            Some(existing) => canonical(&value) < canonical(existing),
-            None => true,
-        };
-
-        if replace {
-            into.insert(key, value);
-        }
-    }
+fn normalize(entry: &mut CommunityListEntry) {
+    entry.seed.community_id = entry.community_id;
+    entry.current.community_id = entry.community_id;
+    normalize_snapshot(&mut entry.seed, &entry.current);
 }
 
-pub(crate) fn canonical<T: Serialize>(value: &T) -> String {
-    serde_json::to_string(value).unwrap_or_default()
+fn normalize_snapshot(seed: &mut JoinMaterial, current: &JoinMaterial) {
+    seed.community_id = current.community_id;
+    seed.name = current.name.clone();
+    seed.relays = current.relays.clone();
+
+    for seed_channel in &mut seed.channels {
+        if let Some(current_channel) = current
+            .channels
+            .iter()
+            .find(|channel| channel.id == seed_channel.id)
+        {
+            seed_channel.name = current_channel.name.clone();
+        }
+    }
 }
 
 fn json_error(error: serde_json::Error) -> ListError {
@@ -358,7 +711,7 @@ mod tests {
     }
 
     #[test]
-    fn a_tombstone_is_terminal_until_a_newer_join_outruns_it() {
+    fn a_tombstone_is_terminal_and_the_entry_it_retires_is_never_written() {
         let owner = Keys::generate().public_key();
         let joined = entry(
             id(0x11),
@@ -378,22 +731,66 @@ mod tests {
         // A stale device re-merging the entry cannot resurrect it.
         assert!(!merge(left.clone(), list(vec![joined.clone()])).is_live(&id(0x11)));
 
-        // A re-join genuinely newer than the removal does.
-        let rejoined = list(vec![entry(
-            id(0x11),
-            material(id(0x11), owner, "Room", 0),
-            material(id(0x11), owner, "Room", 0),
-            7_000,
-        )]);
-        let live = merge(left, rejoined);
-        assert!(live.is_live(&id(0x11)));
+        // The tombstone alone is written, so the entry's key material leaves the wire.
+        let written = serde_json::to_string(&left).expect("writes");
+        assert!(
+            !written.contains("\"entries\""),
+            "a retired entry is not written"
+        );
+        let reparsed: CommunityList = serde_json::from_str(&written).expect("parses");
+        assert_eq!(reparsed.tombstones.len(), 1);
+        assert!(!reparsed.is_live(&id(0x11)));
+
+        // A re-join genuinely newer than the removal does, and is written again.
+        let rejoined = merge(
+            reparsed,
+            list(vec![entry(
+                id(0x11),
+                material(id(0x11), owner, "Room", 0),
+                material(id(0x11), owner, "Room", 0),
+                7_000,
+            )]),
+        );
+        assert!(rejoined.is_live(&id(0x11)));
+        assert!(
+            serde_json::to_string(&rejoined)
+                .expect("writes")
+                .contains("\"entries\"")
+        );
 
         // And the older removal is not re-applied on top of it.
-        assert!(merge(live, removal(id(0x11), 6_000)).is_live(&id(0x11)));
+        assert!(merge(rejoined, removal(id(0x11), 6_000)).is_live(&id(0x11)));
     }
 
     #[test]
-    fn a_second_device_reconstructs_membership_from_13302() {
+    fn frags_disagreement_resolves_to_the_larger_value_and_completeness_is_by_index() {
+        let two = CommunityList {
+            frags: 2,
+            ..Default::default()
+        };
+        let three = CommunityList {
+            frags: 3,
+            ..Default::default()
+        };
+
+        assert_eq!(
+            merge(two.clone(), three.clone()).frags,
+            3,
+            "the larger fragment count wins"
+        );
+        assert_eq!(merge(three.clone(), two).frags, 3);
+
+        assert!(!three.is_complete([0, 1]));
+        assert!(three.is_complete([0, 1, 2]));
+        assert!(three.is_complete([2, 1, 0]), "order does not matter");
+        assert!(
+            three.is_complete([0, 1, 2, 7]),
+            "indices at or above frags are out of range"
+        );
+    }
+
+    #[test]
+    fn a_second_device_reconstructs_membership_from_the_list() {
         let me = Keys::generate();
         let owner = Keys::generate().public_key();
         let mine = CommunityList {
@@ -416,23 +813,32 @@ mod tests {
                 removed_at: AT,
                 extra: Extra::default(),
             }],
-            extra: Extra::default(),
+            ..Default::default()
         };
 
-        let event = build_list_event(&me, &mine).expect("builds");
+        let event = smol::block_on(build_list_event(&me, &mine, 1)).expect("builds");
         assert_eq!(event.kind, Kind::Custom(KIND_COMMUNITY_LIST));
-        assert_eq!(parse_list_event(&me, &event).expect("parses"), mine);
-        assert!(
-            !parse_list_event(&me, &event)
-                .expect("parses")
-                .is_live(&id(0x33))
+        assert_eq!(fragment_index(&event).expect("a fragment index"), 1);
+        assert_eq!(
+            smol::block_on(parse_list_event(&me, &event)).expect("parses"),
+            mine
         );
 
         // Only the member's own keys open it, and an unreadable list is "no news".
         let stranger = Keys::generate();
-        assert!(parse_list_event(&stranger, &event).is_err());
+        assert!(smol::block_on(parse_list_event(&stranger, &event)).is_err());
 
-        // Unknown fields survive the round trip, so a republish cannot wipe them.
+        // A fragment with no `d` tag is not a fragment at all.
+        let untagged = EventBuilder::new(Kind::Custom(KIND_COMMUNITY_LIST), event.content.clone())
+            .finalize(&me)
+            .expect("signs");
+        assert!(matches!(
+            smol::block_on(parse_list_event(&me, &untagged)),
+            Err(ListError::Fragment(_))
+        ));
+
+        // Unknown fields survive the round trip, so a republish cannot wipe them
+        // — including on a channel, where a dropped field destroys key material.
         let mut held = mine.clone();
         held.extra
             .insert("future".to_owned(), serde_json::json!({"deep": [1, 2]}));
@@ -440,8 +846,21 @@ mod tests {
             .current
             .extra
             .insert("held_roots".to_owned(), serde_json::json!([{"epoch": 1}]));
-        let rebuilt =
-            parse_list_event(&me, &build_list_event(&me, &held).expect("builds")).expect("parses");
+        held.entries[0].current.channels = vec![ChannelGrant {
+            id: ChannelId::from_bytes([0x9c; 32]),
+            key: Some("55".repeat(32)),
+            epoch: Epoch(2),
+            name: "staff".to_owned(),
+            extra: Extra::default(),
+        }];
+        held.entries[0].current.channels[0]
+            .extra
+            .insert("read_key".to_owned(), serde_json::json!("aa".repeat(32)));
+        let rebuilt = smol::block_on(parse_list_event(
+            &me,
+            &smol::block_on(build_list_event(&me, &held, 0)).expect("builds"),
+        ))
+        .expect("parses");
         assert_eq!(rebuilt, held);
 
         // The write gate refuses an over-cap or oversized List before publishing.
@@ -459,18 +878,145 @@ mod tests {
                 .collect(),
         );
         assert!(matches!(
-            build_list_event(&me, &crowded),
+            smol::block_on(build_list_event(&me, &crowded, 0)),
             Err(ListError::TooManyMemberships(n)) if n == MAX_MEMBERSHIPS + 1
         ));
 
         let oversized = list(vec![entry(
             id(0x11),
-            material(id(0x11), owner, &"x".repeat(NIP44_MAX_PLAINTEXT), 0),
             material(id(0x11), owner, "Room", 0),
+            material(id(0x11), owner, &"x".repeat(NIP44_MAX_PLAINTEXT), 0),
             AT,
         )]);
         assert!(matches!(oversized.fits(), Err(ListError::Oversize(_))));
     }
 
+    /// The worked example in `examples.md` §6.2, verbatim. Five of its base64url
+    /// values leave non-zero trailing bits, so a strict decoder rejects them.
+    const EXAMPLE: &str = r#"{
+      "frags": 2,
+      "entries": [
+        {
+          "community_id": "PxpVK3nQ7sB1yTfWm4dLxZ0aRcE9uHgKjNvOpQrStUv",
+          "current": {
+            "owner":          "nC7hQ2eRtYuIoPaSdFgHjKlZxCvBnM1qW3eR5tY7uI9",
+            "owner_salt":     "qhEwR9tYuIoPaSdFgHjKlZxCvBnM1qW3eR5tY7uI0oP",
+            "community_root": "d70Xa1QwErTyUiOpAsDfGhJkLzXcVbNm2Qw4Er6Ty8U",
+            "root_epoch":     3,
+            "control_pk":     "DU8vB4nM6qW1eR3tY5uI7oP9aS0dF2gH4jK6lZ8xC0v",
+            "channels": [
+              { "id":  "Ch1dQwErTyUiOpAsDfGhJkLzXcVbNm2Qw4Er6Ty8U0i",
+                "key": "K3yAsDfGhJkLzXcVbNm1Qw2Er3Ty4Ui5Op6As7Df8Gh",
+                "epoch": 2, "name": "staff" }
+            ],
+            "relays": ["wss://relay.example.com"],
+            "name": "Example Community"
+          },
+          "added_at": 1719800000000
+        }
+      ],
+      "tombstones": [
+        { "community_id": "u9RfLmWx3PqZtYvBnKjHgFdSaQwErTyUiOp2C4E6G8I", "removed_at": 1722400000000 }
+      ]
+    }"#;
+
+    #[test]
+    fn the_spec_example_parses_and_the_writer_canonicalizes_it() {
+        let parsed: CommunityList = serde_json::from_str(EXAMPLE).expect("the spec example parses");
+
+        assert_eq!(parsed.frags, 2);
+        assert_eq!(parsed.tombstones.len(), 1);
+
+        let entry = parsed.entries.first().expect("one membership");
+        assert_eq!(entry.current.root_epoch, Epoch(3));
+        assert_eq!(entry.current.name, "Example Community");
+        assert_eq!(entry.current.relays, ["wss://relay.example.com"]);
+        assert!(
+            entry.current.control_root.is_none(),
+            "a non-staff snapshot holds no control_root"
+        );
+        assert_eq!(
+            entry.seed, entry.current,
+            "an absent seed reads as equal to current"
+        );
+
+        let channel = entry.current.channels.first().expect("a private channel");
+        assert_eq!(channel.name, "staff");
+        assert_eq!(channel.epoch, Epoch(2));
+        assert!(channel.key.is_some());
+
+        let written = serde_json::to_string(&parsed).expect("writes");
+        assert!(written.contains("\"frags\":2"));
+        assert!(
+            !written.contains("\"seed\""),
+            "a seed equal to current is omitted"
+        );
+        assert!(
+            !written.contains("\"current\":{\"community_id\""),
+            "an embedded snapshot omits community_id and inherits the entry's"
+        );
+
+        // Every writer emits the canonical spelling, so a non-canonical input is
+        // stabilized here and two devices converge on identical bytes.
+        let value: serde_json::Value = serde_json::from_str(&written).expect("valid");
+        let owner = value["entries"][0]["current"]["owner"]
+            .as_str()
+            .expect("an owner");
+        assert_eq!(owner, base64url::encode(&entry.current.owner.to_bytes()));
+        assert_ne!(owner, "nC7hQ2eRtYuIoPaSdFgHjKlZxCvBnM1qW3eR5tY7uI9");
+
+        // Reading its own output is a fixed point.
+        let again: CommunityList = serde_json::from_str(&written).expect("parses");
+        assert_eq!(again, parsed);
+        assert_eq!(serde_json::to_string(&again).expect("writes"), written);
+    }
+
+    #[test]
+    fn a_rename_rewrites_the_seed_cosmetics_and_collapses_the_snapshot() {
+        let owner = Keys::generate().public_key();
+        let channel = ChannelId::from_bytes([0x9c; 32]);
+
+        let mut current = material(id(0x11), owner, "New name", 5);
+        current.channels = vec![ChannelGrant {
+            id: channel,
+            key: Some("55".repeat(32)),
+            epoch: Epoch(4),
+            name: "new channel".to_owned(),
+            extra: Extra::default(),
+        }];
+
+        let mut seed = material(id(0x11), owner, "Old name", 1);
+        seed.relays = vec!["wss://stale.example".to_owned()];
+        seed.channels = vec![ChannelGrant {
+            id: channel,
+            key: Some("55".repeat(32)),
+            epoch: Epoch(2),
+            name: "old channel".to_owned(),
+            extra: Extra::default(),
+        }];
+
+        let written =
+            serde_json::to_string(&list(vec![entry(id(0x11), seed, current.clone(), AT)]))
+                .expect("writes");
+        let value: serde_json::Value = serde_json::from_str(&written).expect("valid");
+        let written_seed = &value["entries"][0]["seed"];
+        assert_eq!(written_seed["name"], "New name");
+        assert_eq!(written_seed["relays"][0], "wss://relay.example");
+        assert_eq!(written_seed["channels"][0]["name"], "new channel");
+        assert_eq!(
+            written_seed["root_epoch"].as_u64(),
+            Some(1),
+            "the rewrite touches no key material"
+        );
+
+        // A seed that differs from current only in cosmetics is the same bytes
+        // after the rewrite, so it is omitted entirely.
+        let mut stale = material(id(0x11), owner, "Old name", 5);
+        stale.channels = current.channels.clone();
+        let collapsed = serde_json::to_string(&list(vec![entry(id(0x11), stale, current, AT)]))
+            .expect("writes");
+        assert!(!collapsed.contains("\"seed\""));
+    }
+
     const AT: u64 = 1_719_800_000_000;
 }

crates/concord/src/cords/cord02/mod.rs

@@ -4,7 +4,9 @@ pub mod list;
 use std::collections::{BTreeMap, BTreeSet};
 
 use anyhow::{Result, bail};
-use nostr_sdk::prelude::{Event, Keys, PublicKey, Timestamp, UnsignedEvent};
+use nostr_sdk::prelude::{
+    AsyncGetPublicKey, AsyncSignEvent, Event, PublicKey, Timestamp, UnsignedEvent,
+};
 use serde::{Deserialize, Serialize};
 
 use crate::cord01::{KIND_WRAP, SealForm, build_seal, open_wrap_at, wrap_seal_with};
@@ -114,17 +116,24 @@ pub struct CommunityGenesis {
     pub wraps: Vec<Event>,
 }
 
-pub fn genesis(
-    owner: &Keys,
+pub async fn genesis<S>(
+    owner: &S,
     metadata: &CommunityMetadata,
     at_secs: u64,
-) -> Result<CommunityGenesis> {
+) -> Result<CommunityGenesis>
+where
+    S: AsyncGetPublicKey + AsyncSignEvent + ?Sized,
+{
     let metadata_content = encode_metadata(metadata)?;
     let owner_salt = random_32()?;
+    let owner_key = owner
+        .get_public_key_async()
+        .await
+        .map_err(|error| anyhow::anyhow!("signer: {error}"))?;
 
     let identity = CommunityIdentity {
-        community_id: community_id_of(&owner.public_key().to_bytes(), &owner_salt),
-        owner: owner.public_key(),
+        community_id: community_id_of(&owner_key.to_bytes(), &owner_salt),
+        owner: owner_key,
         owner_salt,
     };
 
@@ -167,7 +176,7 @@ pub fn genesis(
     let mut wraps = Vec::with_capacity(editions.len());
 
     for edition in &editions {
-        wraps.push(seal_edition(edition, owner, &read, &signer, at_secs)?);
+        wraps.push(seal_edition(edition, owner, &read, &signer, at_secs).await?);
     }
 
     Ok(CommunityGenesis {
@@ -211,12 +220,15 @@ pub struct Edition<'a> {
 }
 
 impl ControlWriter {
-    pub fn publish(
+    pub async fn publish<S>(
         &self,
-        keys: &Keys,
+        keys: &S,
         edition: Edition<'_>,
         at_secs: u64,
-    ) -> Result<(Event, EntityHead)> {
+    ) -> Result<(Event, EntityHead)>
+    where
+        S: AsyncGetPublicKey + AsyncSignEvent + ?Sized,
+    {
         let rumor = build_edition(EditionFields {
             author: self.author,
             subkind: edition.subkind,
@@ -231,20 +243,23 @@ impl ControlWriter {
         });
 
         let parsed = parse_edition(&rumor)?;
-        let wrap = seal_edition(&rumor, keys, &self.read, &self.signer, at_secs)?;
+        let wrap = seal_edition(&rumor, keys, &self.read, &self.signer, at_secs).await?;
 
         Ok((wrap, EntityHead::from(&parsed)))
     }
 
-    pub fn set_community_metadata(
+    pub async fn set_community_metadata<S>(
         &self,
-        keys: &Keys,
+        keys: &S,
         community_id: &CommunityId,
         metadata: &CommunityMetadata,
         head: Option<&EntityHead>,
         citation: Option<AuthorityCitation>,
         at_secs: u64,
-    ) -> Result<(Event, EntityHead)> {
+    ) -> Result<(Event, EntityHead)>
+    where
+        S: AsyncGetPublicKey + AsyncSignEvent + ?Sized,
+    {
         let content = encode_metadata(metadata)?;
 
         self.publish(
@@ -258,17 +273,21 @@ impl ControlWriter {
             },
             at_secs,
         )
+        .await
     }
 
-    pub fn set_channel_metadata(
+    pub async fn set_channel_metadata<S>(
         &self,
-        keys: &Keys,
+        keys: &S,
         channel: &ChannelId,
         metadata: &ChannelMetadata,
         head: Option<&EntityHead>,
         citation: Option<AuthorityCitation>,
         at_secs: u64,
-    ) -> Result<(Event, EntityHead)> {
+    ) -> Result<(Event, EntityHead)>
+    where
+        S: AsyncGetPublicKey + AsyncSignEvent + ?Sized,
+    {
         if metadata.name.len() > MAX_NAME_BYTES {
             bail!("channel name exceeds {MAX_NAME_BYTES} bytes");
         }
@@ -286,16 +305,20 @@ impl ControlWriter {
             },
             at_secs,
         )
+        .await
     }
 
-    pub fn set_role(
+    pub async fn set_role<S>(
         &self,
-        keys: &Keys,
+        keys: &S,
         role: &Role,
         head: Option<&EntityHead>,
         citation: Option<AuthorityCitation>,
         at_secs: u64,
-    ) -> Result<(Event, EntityHead)> {
+    ) -> Result<(Event, EntityHead)>
+    where
+        S: AsyncGetPublicKey + AsyncSignEvent + ?Sized,
+    {
         if role.name.len() > MAX_NAME_BYTES {
             bail!("role name exceeds {MAX_NAME_BYTES} bytes");
         }
@@ -313,17 +336,21 @@ impl ControlWriter {
             },
             at_secs,
         )
+        .await
     }
 
-    pub fn set_grant(
+    pub async fn set_grant<S>(
         &self,
-        keys: &Keys,
+        keys: &S,
         community_id: &CommunityId,
         grant: &Grant,
         head: Option<&EntityHead>,
         citation: Option<AuthorityCitation>,
         at_secs: u64,
-    ) -> Result<(Event, EntityHead)> {
+    ) -> Result<(Event, EntityHead)>
+    where
+        S: AsyncGetPublicKey + AsyncSignEvent + ?Sized,
+    {
         let content = grant.to_content()?;
 
         self.publish(
@@ -337,17 +364,21 @@ impl ControlWriter {
             },
             at_secs,
         )
+        .await
     }
 
-    pub fn set_banlist(
+    pub async fn set_banlist<S>(
         &self,
-        keys: &Keys,
+        keys: &S,
         community_id: &CommunityId,
         banned: &BTreeSet<PublicKey>,
         head: Option<&EntityHead>,
         citation: Option<AuthorityCitation>,
         at_secs: u64,
-    ) -> Result<(Event, EntityHead)> {
+    ) -> Result<(Event, EntityHead)>
+    where
+        S: AsyncGetPublicKey + AsyncSignEvent + ?Sized,
+    {
         if banned.len() > MAX_BANLIST {
             bail!("banlist exceeds {MAX_BANLIST} entries");
         }
@@ -366,19 +397,23 @@ impl ControlWriter {
             },
             at_secs,
         )
+        .await
     }
 
     #[allow(clippy::too_many_arguments)]
-    pub fn set_registry(
+    pub async fn set_registry<S>(
         &self,
-        keys: &Keys,
+        keys: &S,
         community_id: &CommunityId,
         creator: &PublicKey,
         links: &[PublicKey],
         head: Option<&EntityHead>,
         citation: Option<AuthorityCitation>,
         at_secs: u64,
-    ) -> Result<(Event, EntityHead)> {
+    ) -> Result<(Event, EntityHead)>
+    where
+        S: AsyncGetPublicKey + AsyncSignEvent + ?Sized,
+    {
         let entries: Vec<String> = links
             .iter()
             .take(MAX_REGISTRY_LINKS)
@@ -397,20 +432,24 @@ impl ControlWriter {
             },
             at_secs,
         )
+        .await
     }
 
     /// The whole Pin List, in whichever of CORD-04 §7's two forms the Channel calls for.
     #[allow(clippy::too_many_arguments)]
-    pub fn set_pin_list(
+    pub async fn set_pin_list<S>(
         &self,
-        keys: &Keys,
+        keys: &S,
         community_id: &CommunityId,
         channel: &ChannelId,
         content: &str,
         head: Option<&EntityHead>,
         citation: Option<AuthorityCitation>,
         at_secs: u64,
-    ) -> Result<(Event, EntityHead)> {
+    ) -> Result<(Event, EntityHead)>
+    where
+        S: AsyncGetPublicKey + AsyncSignEvent + ?Sized,
+    {
         self.publish(
             keys,
             Edition {
@@ -422,6 +461,7 @@ impl ControlWriter {
             },
             at_secs,
         )
+        .await
     }
 }
 
@@ -708,14 +748,17 @@ fn authorized_head<'a>(
     selection.head.map(|index| authorized[index])
 }
 
-fn seal_edition(
+async fn seal_edition<S>(
     edition: &UnsignedEvent,
-    owner: &Keys,
+    owner: &S,
     read: &GroupKey,
     signer: &GroupKey,
     at_secs: u64,
-) -> Result<Event> {
-    let seal = build_seal(edition, SealForm::Plaintext, read, owner)?;
+) -> Result<Event>
+where
+    S: AsyncGetPublicKey + AsyncSignEvent + ?Sized,
+{
+    let seal = build_seal(edition, SealForm::Plaintext, read, owner).await?;
 
     let (wrap, _) = wrap_seal_with(
         &seal,
@@ -731,6 +774,8 @@ fn seal_edition(
 
 #[cfg(test)]
 mod tests {
+    use nostr_sdk::prelude::Keys;
+
     use super::*;
     use crate::cord03::{self, build_message, seal_rumor};
     use crate::cord04::pins;
@@ -768,7 +813,7 @@ mod tests {
     #[test]
     fn metadata_and_channel_edits_reach_a_second_client() {
         let owner = Keys::generate();
-        let minted = genesis(&owner, &metadata("coop"), AT).expect("mints");
+        let minted = smol::block_on(genesis(&owner, &metadata("coop"), AT)).expect("mints");
         let community_id = minted.identity.community_id;
         let owner_pk = owner.public_key();
         let (read, signer) = holder(&minted);
@@ -797,33 +842,31 @@ mod tests {
             .get(minted.channel_id.as_bytes())
             .expect("head");
 
-        let (community_wrap, _) = writer
-            .set_community_metadata(
-                &owner,
-                &community_id,
-                &CommunityMetadata {
-                    relays: vec!["wss://relay.example".to_owned()],
-                    ..metadata("coop two")
-                },
-                Some(community_head),
-                None,
-                AT + 1,
-            )
-            .expect("publishes");
-        let (channel_wrap, _) = writer
-            .set_channel_metadata(
-                &owner,
-                &minted.channel_id,
-                &ChannelMetadata {
-                    name: "lobby".to_owned(),
-                    private: false,
-                    ..ChannelMetadata::default()
-                },
-                Some(channel_head),
-                None,
-                AT + 2,
-            )
-            .expect("publishes");
+        let (community_wrap, _) = smol::block_on(writer.set_community_metadata(
+            &owner,
+            &community_id,
+            &CommunityMetadata {
+                relays: vec!["wss://relay.example".to_owned()],
+                ..metadata("coop two")
+            },
+            Some(community_head),
+            None,
+            AT + 1,
+        ))
+        .expect("publishes");
+        let (channel_wrap, _) = smol::block_on(writer.set_channel_metadata(
+            &owner,
+            &minted.channel_id,
+            &ChannelMetadata {
+                name: "lobby".to_owned(),
+                private: false,
+                ..ChannelMetadata::default()
+            },
+            Some(channel_head),
+            None,
+            AT + 2,
+        ))
+        .expect("publishes");
 
         let mut edited = genesis_editions.clone();
         edited.extend(open_all(
@@ -875,7 +918,7 @@ mod tests {
     fn a_delegated_member_edits_metadata_only_under_its_own_grant() {
         let owner = Keys::generate();
         let member = Keys::generate();
-        let minted = genesis(&owner, &metadata("coop"), AT).expect("mints");
+        let minted = smol::block_on(genesis(&owner, &metadata("coop"), AT)).expect("mints");
         let community_id = minted.identity.community_id;
         let owner_pk = owner.public_key();
         let (read, signer) = holder(&minted);
@@ -896,21 +939,20 @@ mod tests {
             extra: Extra::default(),
         };
 
-        let (role_wrap, _) = writer
-            .publish(
-                &owner,
-                Edition {
-                    subkind: vsk::ROLE,
-                    entity: *role_id.as_bytes(),
-                    content: &role.to_content().expect("serializes"),
-                    head: None,
-                    citation: None,
-                },
-                AT + 1,
-            )
-            .expect("publishes");
-        let (grant_wrap, _) = writer
-            .publish(
+        let (role_wrap, _) = smol::block_on(writer.publish(
+            &owner,
+            Edition {
+                subkind: vsk::ROLE,
+                entity: *role_id.as_bytes(),
+                content: &role.to_content().expect("serializes"),
+                head: None,
+                citation: None,
+            },
+            AT + 1,
+        ))
+        .expect("publishes");
+        let (grant_wrap, _) = smol::block_on(
+            writer.publish(
                 &owner,
                 Edition {
                     subkind: vsk::GRANT,
@@ -927,8 +969,9 @@ mod tests {
                     citation: None,
                 },
                 AT + 2,
-            )
-            .expect("publishes");
+            ),
+        )
+        .expect("publishes");
 
         let mut base = open_all(&minted.wraps, &read, &signer.pk());
         base.extend(open_all(&[role_wrap, grant_wrap], &read, &signer.pk()));
@@ -959,36 +1002,34 @@ mod tests {
         };
         let content = serde_json::to_string(&metadata("coop by mod")).expect("serializes");
 
-        let (uncited, _) = member_writer
-            .publish(
-                &member,
-                Edition {
-                    subkind: vsk::COMMUNITY_METADATA,
-                    entity: *community_id.as_bytes(),
-                    content: &content,
-                    head: Some(head),
-                    citation: None,
-                },
-                AT + 3,
-            )
-            .expect("publishes");
-        let (cited, _) = member_writer
-            .publish(
-                &member,
-                Edition {
-                    subkind: vsk::COMMUNITY_METADATA,
-                    entity: *community_id.as_bytes(),
-                    content: &content,
-                    head: Some(head),
-                    citation: Some(AuthorityCitation {
-                        entity: grant.entity,
-                        version: grant.version,
-                        hash: grant.self_hash,
-                    }),
-                },
-                AT + 4,
-            )
-            .expect("publishes");
+        let (uncited, _) = smol::block_on(member_writer.publish(
+            &member,
+            Edition {
+                subkind: vsk::COMMUNITY_METADATA,
+                entity: *community_id.as_bytes(),
+                content: &content,
+                head: Some(head),
+                citation: None,
+            },
+            AT + 3,
+        ))
+        .expect("publishes");
+        let (cited, _) = smol::block_on(member_writer.publish(
+            &member,
+            Edition {
+                subkind: vsk::COMMUNITY_METADATA,
+                entity: *community_id.as_bytes(),
+                content: &content,
+                head: Some(head),
+                citation: Some(AuthorityCitation {
+                    entity: grant.entity,
+                    version: grant.version,
+                    hash: grant.self_hash,
+                }),
+            },
+            AT + 4,
+        ))
+        .expect("publishes");
 
         // Uncited, the edit claims an authority the member never showed.
         let mut forged = base.clone();
@@ -1023,7 +1064,7 @@ mod tests {
     #[test]
     fn a_pin_list_folds_under_its_coordinate_for_a_second_client() {
         let owner = Keys::generate();
-        let minted = genesis(&owner, &metadata("coop"), AT).expect("mints");
+        let minted = smol::block_on(genesis(&owner, &metadata("coop"), AT)).expect("mints");
         let community_id = minted.identity.community_id;
         let owner_pk = owner.public_key();
         let (read, signer) = holder(&minted);
@@ -1042,7 +1083,7 @@ mod tests {
             AT * 1_000,
             None,
         );
-        let (wrap, _) = seal_rumor(&rumor, &group, &author, false).expect("seals");
+        let (wrap, _) = smol::block_on(seal_rumor(&rumor, &group, &author, false)).expect("seals");
         let opened = cord03::open(&wrap, &group, &channel, ROOT_EPOCH)
             .expect("opens")
             .0;
@@ -1064,17 +1105,16 @@ mod tests {
             read: read.clone(),
             signer: signer.clone(),
         };
-        let (pin_wrap, _) = writer
-            .set_pin_list(
-                &owner,
-                &community_id,
-                &channel,
-                &content,
-                None,
-                None,
-                AT + 1,
-            )
-            .expect("publishes");
+        let (pin_wrap, _) = smol::block_on(writer.set_pin_list(
+            &owner,
+            &community_id,
+            &channel,
+            &content,
+            None,
+            None,
+            AT + 1,
+        ))
+        .expect("publishes");
 
         let mut editions = open_all(&minted.wraps, &read, &signer.pk());
         editions.extend(open_all(&[pin_wrap], &read, &signer.pk()));
@@ -1109,7 +1149,7 @@ mod tests {
     #[test]
     fn the_timer_is_never_guessed_and_the_write_caps_hold() {
         let owner = Keys::generate();
-        let minted = genesis(&owner, &metadata("coop"), AT).expect("mints");
+        let minted = smol::block_on(genesis(&owner, &metadata("coop"), AT)).expect("mints");
         let community_id = minted.identity.community_id;
         let owner_pk = owner.public_key();
         let (read, signer) = holder(&minted);
@@ -1124,10 +1164,16 @@ mod tests {
                 &owner_pk,
                 &community_id,
                 &open_all(
-                    &[writer
-                        .set_community_metadata(&owner, &community_id, metadata, None, None, AT + 1)
-                        .expect("publishes")
-                        .0],
+                    &[smol::block_on(writer.set_community_metadata(
+                        &owner,
+                        &community_id,
+                        metadata,
+                        None,
+                        None,
+                        AT + 1,
+                    ))
+                    .expect("publishes")
+                    .0],
                     &writer.read,
                     &writer.signer.pk(),
                 ),
@@ -1163,8 +1209,7 @@ mod tests {
             .map(|_| Keys::generate().public_key())
             .collect();
         assert!(
-            writer
-                .set_banlist(&owner, &community_id, &banned, None, None, AT + 2)
+            smol::block_on(writer.set_banlist(&owner, &community_id, &banned, None, None, AT + 2))
                 .is_err()
         );
 
@@ -1179,20 +1224,19 @@ mod tests {
         assert!(grant.to_content().is_err());
 
         assert!(
-            writer
-                .set_channel_metadata(
-                    &owner,
-                    &minted.channel_id,
-                    &ChannelMetadata {
-                        name: "x".repeat(MAX_NAME_BYTES + 1),
-                        private: false,
-                        ..ChannelMetadata::default()
-                    },
-                    None,
-                    None,
-                    AT + 3,
-                )
-                .is_err()
+            smol::block_on(writer.set_channel_metadata(
+                &owner,
+                &minted.channel_id,
+                &ChannelMetadata {
+                    name: "x".repeat(MAX_NAME_BYTES + 1),
+                    private: false,
+                    ..ChannelMetadata::default()
+                },
+                None,
+                None,
+                AT + 3,
+            ))
+            .is_err()
         );
     }
 }

crates/concord/src/cords/cord03.rs

@@ -1,18 +1,16 @@
 use std::cmp::Reverse;
 use std::collections::BTreeMap;
-use std::fmt;
 
 use anyhow::Result;
 use nostr_sdk::prelude::*;
 
 use crate::cord01::{
-    KIND_WRAP, KIND_WRAP_EPHEMERAL, OpenedStream, SealForm, StreamError, build_rumor_ms,
-    build_seal, channel_binding_tags, check_channel_binding, open_wrap, resolve_ms_strict,
-    wrap_seal,
-};
-use crate::cord04::{
-    AuthorityCitation, TAG_CITATION, canonical_decimal, citation_from, citation_tag,
+    KIND_WRAP, KIND_WRAP_EPHEMERAL, OpenedStream, SealForm, build_rumor_ms, build_seal,
+    channel_binding_tags, check_channel_binding, open_wrap, resolve_ms_strict, wrap_seal,
 };
+use crate::cord04::{AuthorityCitation, canonical_decimal, citation_tag};
+pub use crate::cords::rumor::RumorError as ChatError;
+use crate::cords::rumor::{optional_citation, pubkey, tag, value};
 use crate::derive::channel_group_key;
 use crate::{ChannelId, Epoch, GroupKey, decode_hex_32};
 
@@ -36,42 +34,6 @@ const TAG_TARGET_AUTHOR: &str = "p";
 const TAG_EXPIRATION: &str = "expiration";
 const TAG_TIMER: &str = "timer";
 
-#[derive(Debug)]
-pub enum ChatError {
-    Stream(StreamError),
-    NotEncryptedSealed,
-    UnknownKind(u16),
-    MissingTag(&'static str),
-    DuplicateTag(&'static str),
-    BadTag(&'static str),
-    /// Neither a delete nor a timer notice may be erased by the policy it carries.
-    ExemptExpiration,
-}
-
-impl fmt::Display for ChatError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            ChatError::Stream(error) => write!(f, "stream: {error}"),
-            ChatError::NotEncryptedSealed => write!(f, "chat rumor must ride an encrypted seal"),
-            ChatError::UnknownKind(kind) => write!(f, "not a chat rumor kind: {kind}"),
-            ChatError::MissingTag(name) => write!(f, "missing chat tag: {name}"),
-            ChatError::DuplicateTag(name) => write!(f, "duplicate chat tag: {name}"),
-            ChatError::BadTag(name) => write!(f, "malformed chat tag: {name}"),
-            ChatError::ExemptExpiration => {
-                write!(f, "a delete or timer notice must not carry an expiration")
-            }
-        }
-    }
-}
-
-impl std::error::Error for ChatError {}
-
-impl From<StreamError> for ChatError {
-    fn from(error: StreamError) -> Self {
-        ChatError::Stream(error)
-    }
-}
-
 /// A chat event another chat event refers to: a quote, a comment's parent, a reaction's target.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct ReplyRef {
@@ -292,19 +254,22 @@ pub fn build_typing(
 }
 
 /// `ephemeral` picks the 21059 wrap, which relays must not store.
-pub fn seal_rumor(
+pub async fn seal_rumor<S>(
     rumor: &UnsignedEvent,
     group: &GroupKey,
-    author: &Keys,
+    author: &S,
     ephemeral: bool,
-) -> Result<(Event, Keys), ChatError> {
+) -> Result<(Event, Keys), ChatError>
+where
+    S: AsyncGetPublicKey + AsyncSignEvent + ?Sized,
+{
     let kind = rumor.kind.as_u16();
 
     if !is_chat_kind(kind) {
         return Err(ChatError::UnknownKind(kind));
     }
 
-    let seal = build_seal(rumor, SealForm::Encrypted, group, author)?;
+    let seal = build_seal(rumor, SealForm::Encrypted, group, author).await?;
     let wrap_kind = if ephemeral {
         KIND_WRAP_EPHEMERAL
     } else {
@@ -576,16 +541,6 @@ fn optional_kind(rumor: &UnsignedEvent, name: &'static str) -> Result<Option<u16
         .map_err(|_| ChatError::BadTag(name))
 }
 
-fn optional_citation(rumor: &UnsignedEvent) -> Result<Option<AuthorityCitation>, ChatError> {
-    let Some(fields) = tag(rumor, TAG_CITATION)? else {
-        return Ok(None);
-    };
-
-    citation_from(fields)
-        .map(Some)
-        .ok_or(ChatError::BadTag(TAG_CITATION))
-}
-
 pub fn expiration_of(rumor: &UnsignedEvent) -> Result<Option<Timestamp>, ChatError> {
     let Some(fields) = tag(rumor, TAG_EXPIRATION)? else {
         return Ok(None);
@@ -611,51 +566,16 @@ fn reply_tag(name: &str, reply: &ReplyRef) -> Tag {
     )
 }
 
-fn tag<'a>(
-    rumor: &'a UnsignedEvent,
-    name: &'static str,
-) -> Result<Option<&'a [String]>, ChatError> {
-    let mut found: Option<&[String]> = None;
-
-    for candidate in rumor.tags.iter() {
-        let fields = candidate.as_slice();
-
-        if fields.first().map(String::as_str) != Some(name) {
-            continue;
-        }
-
-        if found.is_some() {
-            return Err(ChatError::DuplicateTag(name));
-        }
-
-        found = Some(fields);
-    }
-
-    Ok(found)
-}
-
-fn value<'a>(fields: &'a [String], name: &'static str) -> Result<&'a str, ChatError> {
-    fields
-        .get(1)
-        .map(String::as_str)
-        .ok_or(ChatError::BadTag(name))
-}
-
 fn hex_id(fields: &[String], name: &'static str) -> Result<EventId, ChatError> {
     let bytes = decode_hex_32(value(fields, name)?).map_err(|_| ChatError::BadTag(name))?;
 
     EventId::from_slice(&bytes).map_err(|_| ChatError::BadTag(name))
 }
 
-fn pubkey(hex: &str, name: &'static str) -> Result<PublicKey, ChatError> {
-    let bytes = decode_hex_32(hex).map_err(|_| ChatError::BadTag(name))?;
-
-    PublicKey::from_slice(&bytes).map_err(|_| ChatError::BadTag(name))
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::cord01::StreamError;
 
     const SECRET: [u8; 32] = [0x2du8; 32];
     const AT: u64 = 1_700_000_000_417;
@@ -674,7 +594,9 @@ mod tests {
     }
 
     fn sealed(rumor: &UnsignedEvent, group: &GroupKey, author: &Keys) -> Event {
-        seal_rumor(rumor, group, author, false).expect("seals").0
+        smol::block_on(seal_rumor(rumor, group, author, false))
+            .expect("seals")
+            .0
     }
 
     fn read(rumor: &UnsignedEvent, group: &GroupKey, author: &Keys, epoch: Epoch) -> ChatRumor {
@@ -949,7 +871,8 @@ mod tests {
 
         // Chat is encrypted-seal only (CORD-02 §5), and a retired kind is not a
         // chat rumor however well-formed it looks.
-        let seal = build_seal(&plain, SealForm::Plaintext, &group, &alice).expect("seals");
+        let seal =
+            smol::block_on(build_seal(&plain, SealForm::Plaintext, &group, &alice)).expect("seals");
         let (wrap, _) = wrap_seal(
             &seal,
             &group,
@@ -971,7 +894,7 @@ mod tests {
             AT,
         );
         assert!(matches!(
-            seal_rumor(&ghost, &group, &alice, false),
+            smol::block_on(seal_rumor(&ghost, &group, &alice, false)),
             Err(ChatError::UnknownKind(3300))
         ));
 

crates/concord/src/cords/cord04/mod.rs

@@ -121,7 +121,7 @@ fn signing_bytes(
     bytes
 }
 
-pub fn edition_hash(
+fn edition_hash(
     entity: &[u8; 32],
     version: u64,
     prev: Option<&[u8; 32]>,
@@ -246,14 +246,14 @@ impl From<&ParsedEdition> for EditionMeta {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
-pub struct FoldResult {
+struct FoldResult {
     pub head: Option<usize>,
     pub gap: bool,
     pub anchored: bool,
 }
 
 /// The highest version whose chain is intact, given a held floor.
-pub fn fold(editions: &[EditionMeta], floor: u64, floor_hash: Option<&[u8; 32]>) -> FoldResult {
+fn fold(editions: &[EditionMeta], floor: u64, floor_hash: Option<&[u8; 32]>) -> FoldResult {
     let mut by_version: BTreeMap<u64, usize> = BTreeMap::new();
 
     for (index, edition) in editions.iter().enumerate() {
@@ -311,7 +311,7 @@ pub fn fold(editions: &[EditionMeta], floor: u64, floor_hash: Option<&[u8; 32]>)
 }
 
 /// The highest version overall, ignoring contiguity.
-pub fn bootstrap_head(editions: &[EditionMeta]) -> Option<usize> {
+fn bootstrap_head(editions: &[EditionMeta]) -> Option<usize> {
     editions
         .iter()
         .enumerate()

crates/concord/src/cords/cord04/pins.rs

@@ -583,7 +583,7 @@ mod tests {
             at_ms,
             None,
         );
-        let (wrap, _) = seal_rumor(&rumor, &group(), author, false).expect("seals");
+        let (wrap, _) = smol::block_on(seal_rumor(&rumor, &group(), author, false)).expect("seals");
 
         open(&wrap, &group(), &channel(), Epoch(0)).expect("opens")
     }
@@ -699,7 +699,7 @@ mod tests {
             AT_MS + 5_000,
             None,
         );
-        let (wrap, _) = seal_rumor(&edit, &group(), &author, false).expect("seals");
+        let (wrap, _) = smol::block_on(seal_rumor(&edit, &group(), &author, false)).expect("seals");
         let (edit_opened, _) = open(&wrap, &group(), &channel(), Epoch(0)).expect("opens");
 
         let refreshed = with_proven_edit(&entry, &edit_opened, &group(), &channel());
@@ -718,7 +718,8 @@ mod tests {
             AT_MS + 6_000,
             None,
         );
-        let (wrap, _) = seal_rumor(&hijack, &group(), &stranger, false).expect("seals");
+        let (wrap, _) =
+            smol::block_on(seal_rumor(&hijack, &group(), &stranger, false)).expect("seals");
         let (hijack_opened, _) = open(&wrap, &group(), &channel(), Epoch(0)).expect("opens");
 
         let unchanged = with_proven_edit(&entry, &hijack_opened, &group(), &channel());
@@ -805,7 +806,8 @@ mod tests {
                 None,
                 AT_MS + 1_000,
             );
-            let (wrap, _) = seal_rumor(&delete, &group(), author_keys, false).expect("seals");
+            let (wrap, _) =
+                smol::block_on(seal_rumor(&delete, &group(), author_keys, false)).expect("seals");
             let (_, rumor) = open(&wrap, &group(), &channel(), Epoch(0)).expect("opens");
 
             assert_eq!(

crates/concord/src/cords/cord04/roles.rs

@@ -100,7 +100,7 @@ pub struct Role {
 }
 
 impl Role {
-    pub fn parse(content: &str) -> Option<Self> {
+    fn parse(content: &str) -> Option<Self> {
         serde_json::from_str(content).ok()
     }
 
@@ -122,7 +122,7 @@ pub struct Grant {
 }
 
 impl Grant {
-    pub fn parse(content: &str) -> Option<Self> {
+    fn parse(content: &str) -> Option<Self> {
         serde_json::from_str(content).ok()
     }
 
@@ -135,7 +135,7 @@ impl Grant {
     }
 }
 
-pub fn parse_banlist(content: &str) -> Option<Vec<PublicKey>> {
+fn parse_banlist(content: &str) -> Option<Vec<PublicKey>> {
     let entries: Vec<String> = serde_json::from_str(content).ok()?;
     let mut banned = Vec::with_capacity(entries.len());
 

crates/concord/src/cords/cord05.rs

@@ -11,10 +11,10 @@ use nostr_sdk::prelude::*;
 use serde::{Deserialize, Serialize};
 
 use crate::cord01::{self, NIP44_MAX_PLAINTEXT, StreamError};
-use crate::cord02::list::{canonical, union};
 use crate::cord02::{ImageRef, MAX_RELAYS};
 use crate::cord04::{TAG_SUBKIND, vsk};
 use crate::derive::{TOKEN_LEN, verify_community_id};
+use crate::utils::{canonical, union};
 use crate::{ChannelId, CommunityId, Epoch, Extra, decode_hex_32};
 
 pub const KIND_BUNDLE: u16 = 33301;
@@ -447,16 +447,19 @@ pub fn parse_link(input: &str) -> Result<ParsedInviteLink, InviteError> {
     })
 }
 
-pub fn build_direct_invite(
-    inviter: &Keys,
+pub async fn build_direct_invite<S>(
+    inviter: &S,
     recipient: &PublicKey,
     invite: &CommunityInvite,
-) -> Result<Event, InviteError> {
+) -> Result<Event, InviteError>
+where
+    S: AsyncGetPublicKey + AsyncSignEvent + AsyncNip44,
+{
     invite.validate()?;
 
     let json = serde_json::to_string(invite).map_err(json_error)?;
-    let rumor = EventBuilder::new(Kind::Custom(KIND_DIRECT_INVITE), json)
-        .finalize_unsigned(inviter.public_key());
+    let author = inviter.get_public_key_async().await.map_err(crypto_error)?;
+    let rumor = EventBuilder::new(Kind::Custom(KIND_DIRECT_INVITE), json).finalize_unsigned(author);
 
     let mut tags = vec![Tag::custom("k", [KIND_DIRECT_INVITE.to_string()])];
 
@@ -469,15 +472,22 @@ pub fn build_direct_invite(
 
     GiftWrapBuilder::new(*recipient, rumor)
         .extra_tags(tags)
-        .finalize(inviter)
+        .finalize_async(inviter)
+        .await
         .map_err(crypto_error)
 }
 
-pub fn unwrap_direct_invite(
+/// The NIP-59 unwrap is `Sized`-bounded in the SDK, so this stays `Sized` too.
+pub async fn unwrap_direct_invite<S>(
     wrap: &Event,
-    recipient: &Keys,
-) -> Result<(PublicKey, CommunityInvite), InviteError> {
-    let unwrapped = UnwrappedGift::from_gift_wrap(recipient, wrap).map_err(crypto_error)?;
+    recipient: &S,
+) -> Result<(PublicKey, CommunityInvite), InviteError>
+where
+    S: AsyncNip44,
+{
+    let unwrapped = UnwrappedGift::from_gift_wrap_async(recipient, wrap)
+        .await
+        .map_err(crypto_error)?;
 
     if unwrapped.rumor.kind.as_u16() != KIND_DIRECT_INVITE {
         return Err(InviteError::BadEvent("rumor is not a direct invite"));
@@ -590,25 +600,32 @@ pub fn merge_invite_lists(held: InviteList, incoming: InviteList) -> InviteList
     }
 }
 
-pub fn build_invite_list(keys: &Keys, list: &InviteList) -> Result<Event, InviteError> {
+pub async fn build_invite_list<S>(keys: &S, list: &InviteList) -> Result<Event, InviteError>
+where
+    S: AsyncGetPublicKey + AsyncSignEvent + AsyncNip44 + ?Sized,
+{
     list.fits()?;
 
     let json = serde_json::to_string(list).map_err(json_error)?;
-    let content = cord01::seal_to_self(keys, json.as_bytes())?;
+    let content = cord01::seal_to_self(keys, &json).await?;
 
     EventBuilder::new(Kind::Custom(KIND_INVITE_LIST), content)
-        .finalize(keys)
+        .finalize_async(keys)
+        .await
         .map_err(crypto_error)
 }
 
-pub fn parse_invite_list(keys: &Keys, event: &Event) -> Result<InviteList, InviteError> {
+pub async fn parse_invite_list<S>(keys: &S, event: &Event) -> Result<InviteList, InviteError>
+where
+    S: AsyncGetPublicKey + AsyncNip44 + ?Sized,
+{
     if event.kind.as_u16() != KIND_INVITE_LIST {
         return Err(InviteError::Kind(event.kind.as_u16()));
     }
 
-    let json = cord01::open_to_self(keys, &event.content)?;
+    let json = cord01::open_to_self(keys, &event.content).await?;
 
-    serde_json::from_slice(&json).map_err(json_error)
+    serde_json::from_str(&json).map_err(json_error)
 }
 
 /// An entry is immutable once minted, so two copies should agree.
@@ -920,7 +937,12 @@ mod tests {
         let recipient = Keys::generate();
         let invite = bundle();
 
-        let wrap = build_direct_invite(&inviter, &recipient.public_key(), &invite).expect("builds");
+        let wrap = smol::block_on(build_direct_invite(
+            &inviter,
+            &recipient.public_key(),
+            &invite,
+        ))
+        .expect("builds");
         assert_eq!(wrap.kind, Kind::GiftWrap);
         assert_ne!(
             wrap.pubkey,
@@ -932,13 +954,14 @@ mod tests {
             "the k tag is what makes an invite indexable"
         );
 
-        let (sender, opened) = unwrap_direct_invite(&wrap, &recipient).expect("unwraps");
+        let (sender, opened) =
+            smol::block_on(unwrap_direct_invite(&wrap, &recipient)).expect("unwraps");
         assert_eq!(sender, inviter.public_key());
         assert_eq!(opened.community_id, invite.community_id);
 
         // Somebody else's wrap is not ours to open...
         let stranger = Keys::generate();
-        assert!(unwrap_direct_invite(&wrap, &stranger).is_err());
+        assert!(smol::block_on(unwrap_direct_invite(&wrap, &stranger)).is_err());
 
         // ...and a wrap that opens to some other kind is not an invite.
         let rumor = EventBuilder::new(Kind::Custom(crate::cord03::KIND_MESSAGE), "hello")
@@ -947,7 +970,7 @@ mod tests {
             .finalize(&recipient)
             .expect("wraps");
         assert!(matches!(
-            unwrap_direct_invite(&wrap, &recipient),
+            smol::block_on(unwrap_direct_invite(&wrap, &recipient)),
             Err(InviteError::BadEvent(_))
         ));
     }

crates/concord/src/cords/cord06.rs

@@ -2,9 +2,10 @@ use std::collections::{BTreeMap, BTreeSet};
 use std::fmt;
 
 use anyhow::Result;
-use data_encoding::HEXLOWER;
-use nostr::nips::nip44::v2::ConversationKey;
-use nostr_sdk::prelude::{Event, Keys, PublicKey, SecretKey, Tag, Timestamp, UnsignedEvent};
+use data_encoding::{BASE64, HEXLOWER};
+use nostr_sdk::prelude::{
+    AsyncGetPublicKey, AsyncNip44, AsyncSignEvent, Event, PublicKey, Tag, Timestamp, UnsignedEvent,
+};
 use serde::{Deserialize, Serialize};
 
 use crate::cord01::{self, KIND_SEAL_PLAINTEXT, OpenedStream, SealForm, StreamError};
@@ -298,34 +299,48 @@ pub fn blob_locator(
     ))
 }
 
-pub fn build_blob(
-    rotator: &Keys,
+pub async fn build_blob<S>(
+    rotator: &S,
     recipient: &PublicKey,
     scope: RekeyScope,
     epoch: Epoch,
     new_key: &[u8; 32],
     control_pk: Option<&[u8; 32]>,
     control_root: Option<&[u8; 32]>,
-) -> Result<RekeyBlob, RekeyError> {
+) -> Result<RekeyBlob, RekeyError>
+where
+    S: AsyncGetPublicKey + AsyncNip44 + ?Sized,
+{
     let plaintext = encode_blob_plaintext(scope, epoch, new_key, control_pk, control_root)?;
+    let rotator_pk = rotator.get_public_key_async().await.map_err(crypto_error)?;
+
+    let wrapped = rotator
+        .nip44_encrypt_async(recipient, &BASE64.encode(&plaintext))
+        .await
+        .map_err(crypto_error)?;
 
     Ok(RekeyBlob {
-        locator: blob_locator(&rotator.public_key(), recipient, scope, epoch),
-        wrapped: seal_to(rotator.secret_key(), recipient, &plaintext)?,
+        locator: blob_locator(&rotator_pk, recipient, scope, epoch),
+        wrapped,
     })
 }
 
-pub fn open_blob(
-    recipient: &Keys,
+pub async fn open_blob<S>(
+    recipient: &S,
     rotator: &PublicKey,
     scope: RekeyScope,
     epoch: Epoch,
     blob: &RekeyBlob,
     community_id: &CommunityId,
-) -> Result<KeyDelivery, RekeyError> {
-    let conversation =
-        ConversationKey::derive(recipient.secret_key(), rotator).map_err(crypto_error)?;
-    let plaintext = cord01::open_bytes(&conversation, &blob.wrapped)?;
+) -> Result<KeyDelivery, RekeyError>
+where
+    S: AsyncNip44 + ?Sized,
+{
+    let text = recipient
+        .nip44_decrypt_async(rotator, &blob.wrapped)
+        .await
+        .map_err(crypto_error)?;
+    let plaintext = BASE64.decode(text.as_bytes()).map_err(crypto_error)?;
 
     parse_blob_plaintext(&plaintext, scope, epoch, community_id)
 }
@@ -341,15 +356,6 @@ pub fn find_my_blobs<'a>(
     blobs.iter().filter(move |blob| blob.locator == wanted)
 }
 
-fn seal_to(
-    secret: &SecretKey,
-    recipient: &PublicKey,
-    plaintext: &[u8],
-) -> Result<String, RekeyError> {
-    let conversation = ConversationKey::derive(secret, recipient).map_err(crypto_error)?;
-    Ok(cord01::seal_bytes(&conversation, plaintext)?)
-}
-
 #[derive(Debug, Clone)]
 pub struct RekeyChunk {
     pub rotator: PublicKey,
@@ -598,8 +604,8 @@ pub fn build_rekey_rumor(
 }
 
 #[allow(clippy::too_many_arguments)]
-pub fn build_rekey_chunks(
-    rotator: &Keys,
+pub async fn build_rekey_chunks<S>(
+    rotator: &S,
     group: &GroupKey,
     scope: RekeyScope,
     new_epoch: Epoch,
@@ -609,7 +615,11 @@ pub fn build_rekey_chunks(
     citation: Option<&AuthorityCitation>,
     severed: bool,
     at_secs: u64,
-) -> Result<Vec<Event>, RekeyError> {
+) -> Result<Vec<Event>, RekeyError>
+where
+    S: AsyncGetPublicKey + AsyncSignEvent + ?Sized,
+{
+    let rotator_key = rotator.get_public_key_async().await.map_err(crypto_error)?;
     let mut groups: Vec<&[RekeyBlob]> = blobs.chunks(MAX_REKEY_BLOBS_PER_EVENT).collect();
 
     if groups.is_empty() {
@@ -621,7 +631,7 @@ pub fn build_rekey_chunks(
 
     for (index, group_blobs) in groups.into_iter().enumerate() {
         let rumor = build_rekey_rumor(
-            rotator.public_key(),
+            rotator_key,
             scope,
             new_epoch,
             prev_epoch,
@@ -633,7 +643,7 @@ pub fn build_rekey_chunks(
             at_secs,
         )?;
 
-        let seal = cord01::build_seal(&rumor, SealForm::Encrypted, group, rotator)?;
+        let seal = cord01::build_seal(&rumor, SealForm::Encrypted, group, rotator).await?;
         let (wrap, _) = cord01::wrap_seal(
             &seal,
             group,
@@ -731,14 +741,17 @@ pub fn dissolved_tombstone_rumor(
     )
 }
 
-pub fn seal_dissolved(
+pub async fn seal_dissolved<S>(
     rumor: &UnsignedEvent,
     community_id: &CommunityId,
-    owner: &Keys,
+    owner: &S,
     at_secs: u64,
-) -> Result<Event, RekeyError> {
+) -> Result<Event, RekeyError>
+where
+    S: AsyncGetPublicKey + AsyncSignEvent + ?Sized,
+{
     let group = dissolved_group_key(community_id).map_err(crypto_error)?;
-    let seal = cord01::build_seal(rumor, SealForm::Plaintext, &group, owner)?;
+    let seal = cord01::build_seal(rumor, SealForm::Plaintext, &group, owner).await?;
     let (wrap, _) = cord01::wrap_seal(
         &seal,
         &group,
@@ -858,6 +871,8 @@ fn crypto_error(error: impl fmt::Display) -> RekeyError {
 mod tests {
     use std::collections::BTreeSet;
 
+    use nostr_sdk::prelude::Keys;
+
     use super::*;
     use crate::cord01::KIND_WRAP;
     use crate::cord02::{
@@ -912,16 +927,16 @@ mod tests {
         let scope = RekeyScope::Channel(channel());
 
         let open = |keys: &Keys, scope: RekeyScope, epoch: Epoch, blob: &RekeyBlob| {
-            open_blob(
+            smol::block_on(open_blob(
                 keys,
                 &rotator.public_key(),
                 scope,
                 epoch,
                 blob,
                 &community_id,
-            )
+            ))
         };
-        let blob = build_blob(
+        let blob = smol::block_on(build_blob(
             &rotator,
             &recipient.public_key(),
             scope,
@@ -929,7 +944,7 @@ mod tests {
             &key,
             None,
             None,
-        )
+        ))
         .expect("builds");
 
         assert_eq!(
@@ -962,7 +977,7 @@ mod tests {
             .to_bytes();
 
         let base = |pk: Option<&[u8; 32]>, root: Option<&[u8; 32]>| {
-            build_blob(
+            smol::block_on(build_blob(
                 &rotator,
                 &recipient.public_key(),
                 RekeyScope::Base,
@@ -970,7 +985,7 @@ mod tests {
                 &key,
                 pk,
                 root,
-            )
+            ))
             .expect("builds")
         };
 
@@ -1043,7 +1058,7 @@ mod tests {
         let community_id = community();
 
         let blob_for = |recipient: &Keys, key: [u8; 32]| {
-            build_blob(
+            smol::block_on(build_blob(
                 &rotator,
                 &recipient.public_key(),
                 scope,
@@ -1051,7 +1066,7 @@ mod tests {
                 &key,
                 None,
                 None,
-            )
+            ))
             .expect("builds")
         };
         let mine = blob_for(&me, [0xAA; 32]);
@@ -1059,7 +1074,7 @@ mod tests {
 
         let group = rekey_group(scope, &ROOT, &community_id, epoch).expect("derives");
         let prior_commit = epoch_key_commitment(Epoch(0), &PRIOR_KEY);
-        let chunks = build_rekey_chunks(
+        let chunks = smol::block_on(build_rekey_chunks(
             &rotator,
             &group,
             scope,
@@ -1070,7 +1085,7 @@ mod tests {
             None,
             false,
             AT,
-        )
+        ))
         .expect("builds");
         assert_eq!(chunks.len(), 1);
 
@@ -1129,14 +1144,14 @@ mod tests {
         .next()
         .expect("located");
         assert_eq!(
-            open_blob(
+            smol::block_on(open_blob(
                 &me,
                 &rotator.public_key(),
                 scope,
                 epoch,
                 located,
                 &community_id
-            )
+            ))
             .expect("opens")
             .new_key,
             [0xAA; 32]
@@ -1269,26 +1284,26 @@ mod tests {
         content: String,
         at_secs: u64,
     ) -> Event {
-        writer
-            .publish(
-                owner,
-                Edition {
-                    subkind,
-                    entity,
-                    content: &content,
-                    head: None,
-                    citation: None,
-                },
-                at_secs,
-            )
-            .expect("publishes")
-            .0
+        smol::block_on(writer.publish(
+            owner,
+            Edition {
+                subkind,
+                entity,
+                content: &content,
+                head: None,
+                citation: None,
+            },
+            at_secs,
+        ))
+        .expect("publishes")
+        .0
     }
 
     #[test]
     fn a_rotation_needs_the_permission_and_must_strictly_outrank_every_target() {
         let owner = Keys::generate();
-        let minted = genesis(&owner, &CommunityMetadata::default(), AT).expect("mints");
+        let minted =
+            smol::block_on(genesis(&owner, &CommunityMetadata::default(), AT)).expect("mints");
         let community_id = minted.identity.community_id;
         let read =
             control_group_key(&minted.community_root, &community_id, ROOT_EPOCH).expect("derives");
@@ -1413,7 +1428,7 @@ mod tests {
             .map(|_| {
                 let member = Keys::generate();
 
-                build_blob(
+                smol::block_on(build_blob(
                     &rotator,
                     &member.public_key(),
                     scope,
@@ -1421,12 +1436,12 @@ mod tests {
                     &[0xCD; 32],
                     None,
                     None,
-                )
+                ))
                 .expect("builds")
             })
             .collect();
 
-        let chunks = build_rekey_chunks(
+        let chunks = smol::block_on(build_rekey_chunks(
             &rotator,
             &group,
             scope,
@@ -1437,7 +1452,7 @@ mod tests {
             None,
             false,
             AT,
-        )
+        ))
         .expect("builds");
 
         assert_eq!(chunks.len(), 1, "a full send chunk is one event");
@@ -1452,7 +1467,7 @@ mod tests {
             wrapped: "x".to_owned(),
         });
 
-        let chunks = build_rekey_chunks(
+        let chunks = smol::block_on(build_rekey_chunks(
             &rotator,
             &group,
             scope,
@@ -1463,7 +1478,7 @@ mod tests {
             None,
             false,
             AT,
-        )
+        ))
         .expect("builds");
 
         assert_eq!(chunks.len(), 2, "one over the cap splits across two events");
@@ -1485,8 +1500,13 @@ mod tests {
             content: "{}",
             at_secs: AT,
         });
-        let seal =
-            cord01::build_seal(&rumor, SealForm::Plaintext, &prior_read, &owner).expect("seals");
+        let seal = smol::block_on(cord01::build_seal(
+            &rumor,
+            SealForm::Plaintext,
+            &prior_read,
+            &owner,
+        ))
+        .expect("seals");
 
         let refounding = plan_refounding(Epoch(1)).expect("plans");
         let read = refounding.read(&community_id).expect("derives");
@@ -1507,8 +1527,13 @@ mod tests {
         assert_eq!(reopened.author, owner.public_key());
 
         // Only a plaintext seal can be carried forward.
-        let encrypted =
-            cord01::build_seal(&rumor, SealForm::Encrypted, &prior_read, &owner).expect("seals");
+        let encrypted = smol::block_on(cord01::build_seal(
+            &rumor,
+            SealForm::Encrypted,
+            &prior_read,
+            &owner,
+        ))
+        .expect("seals");
         assert!(matches!(
             compact(&[encrypted], &read, &signer, AT + 1),
             Err(RekeyError::Stream(StreamError::NotRewrappable))
@@ -1527,7 +1552,8 @@ mod tests {
         };
 
         let rumor = dissolved_tombstone_rumor(owner.public_key(), &community_id, AT);
-        let wrap = seal_dissolved(&rumor, &community_id, &owner, AT).expect("seals");
+        let wrap =
+            smol::block_on(seal_dissolved(&rumor, &community_id, &owner, AT)).expect("seals");
 
         assert!(verify_dissolved(&wrap, &identity));
         assert_eq!(
@@ -1538,18 +1564,18 @@ mod tests {
         // Anyone holding the community id finds the address, but only the committed
         // owner's signature counts.
         let impostor = Keys::generate();
-        let forged = seal_dissolved(
+        let forged = smol::block_on(seal_dissolved(
             &dissolved_tombstone_rumor(impostor.public_key(), &community_id, AT),
             &community_id,
             &impostor,
             AT,
-        )
+        ))
         .expect("seals");
         assert!(!verify_dissolved(&forged, &identity));
 
         // The spec's all-zero `eid` is refused: it would let one owner's genuine
         // tombstone be re-wrapped at another of their communities and kill it.
-        let zeroed = seal_dissolved(
+        let zeroed = smol::block_on(seal_dissolved(
             &cord01::build_rumor_secs(
                 KIND_CONTROL,
                 owner.public_key(),
@@ -1563,7 +1589,7 @@ mod tests {
             &community_id,
             &owner,
             AT,
-        )
+        ))
         .expect("seals");
         assert!(matches!(
             open_dissolved(&zeroed, &community_id),

crates/concord/src/cords/mod.rs

@@ -1,5 +1,4 @@
-//! One module per CORD document. CORD-07 (audio/video) is unimplemented, and
-//! CORD-08's timer rides the Chat and Control planes it edits rather than owning a file.
+mod rumor;
 
 pub mod cord01;
 pub mod cord02;

crates/concord/src/cords/rumor.rs

@@ -0,0 +1,96 @@
+use std::fmt;
+
+use nostr_sdk::prelude::*;
+
+use crate::cord01::StreamError;
+use crate::cord04::{AuthorityCitation, TAG_CITATION, citation_from};
+use crate::decode_hex_32;
+
+#[derive(Debug)]
+pub enum RumorError {
+    Stream(StreamError),
+    NotEncryptedSealed,
+    UnknownKind(u16),
+    MissingTag(&'static str),
+    DuplicateTag(&'static str),
+    BadTag(&'static str),
+    /// Neither a delete nor a timer notice may be erased by the policy it carries.
+    ExemptExpiration,
+}
+
+impl fmt::Display for RumorError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            RumorError::Stream(error) => write!(f, "stream: {error}"),
+            RumorError::NotEncryptedSealed => write!(f, "rumor must ride an encrypted seal"),
+            RumorError::UnknownKind(kind) => write!(f, "not a rumor kind: {kind}"),
+            RumorError::MissingTag(name) => write!(f, "missing tag: {name}"),
+            RumorError::DuplicateTag(name) => write!(f, "duplicate tag: {name}"),
+            RumorError::BadTag(name) => write!(f, "malformed tag: {name}"),
+            RumorError::ExemptExpiration => {
+                write!(f, "a delete or timer notice must not carry an expiration")
+            }
+        }
+    }
+}
+
+impl std::error::Error for RumorError {}
+
+impl From<StreamError> for RumorError {
+    fn from(error: StreamError) -> Self {
+        RumorError::Stream(error)
+    }
+}
+
+pub fn tag<'a>(
+    rumor: &'a UnsignedEvent,
+    name: &'static str,
+) -> Result<Option<&'a [String]>, RumorError> {
+    let mut found: Option<&[String]> = None;
+
+    for candidate in rumor.tags.iter() {
+        let fields = candidate.as_slice();
+
+        if fields.first().map(String::as_str) != Some(name) {
+            continue;
+        }
+
+        if found.is_some() {
+            return Err(RumorError::DuplicateTag(name));
+        }
+
+        found = Some(fields);
+    }
+
+    Ok(found)
+}
+
+pub fn required<'a>(
+    rumor: &'a UnsignedEvent,
+    name: &'static str,
+) -> Result<&'a [String], RumorError> {
+    tag(rumor, name)?.ok_or(RumorError::MissingTag(name))
+}
+
+pub fn value<'a>(fields: &'a [String], name: &'static str) -> Result<&'a str, RumorError> {
+    fields
+        .get(1)
+        .map(String::as_str)
+        .ok_or(RumorError::BadTag(name))
+}
+
+pub fn pubkey(hex: &str, name: &'static str) -> Result<PublicKey, RumorError> {
+    let bytes = decode_hex_32(hex).map_err(|_| RumorError::BadTag(name))?;
+
+    PublicKey::from_slice(&bytes).map_err(|_| RumorError::BadTag(name))
+}
+
+pub fn optional_citation(rumor: &UnsignedEvent) -> Result<Option<AuthorityCitation>, RumorError> {
+    let Some(fields) = tag(rumor, TAG_CITATION)? else {
+        return Ok(None);
+    };
+
+    citation_from(fields)
+        .map(Some)
+        .ok_or(RumorError::BadTag(TAG_CITATION))
+}

crates/concord/src/store.rs

@@ -23,7 +23,8 @@ const MARK_TAG: SingleLetterTag = SingleLetterTag::LOWERCASE_T;
 const MARK_VALUE: &str = "concord";
 const WRAP_TAG: &str = "e";
 const KIND_TAG: &str = "k";
-const STATE_PREFIX: &str = "concord/";
+/// The `concord/` namespace for locally-keyed documents.
+pub const STATE_PREFIX: &str = "concord/";
 
 /// An already-expired rumor is refused at ingest. Returns whether it was kept.
 pub async fn cache_rumor(
@@ -91,7 +92,7 @@ pub async fn purge_expired(client: &Client, channel: &ChannelId, now: Timestamp)
 }
 
 pub async fn query_rumors(
-    database: &dyn NostrDatabase,
+    client: &Client,
     channel: &ChannelId,
     until: Option<Timestamp>,
     limit: usize,
@@ -106,7 +107,7 @@ pub async fn query_rumors(
     }
 
     let mut newest: BTreeMap<String, Event> = BTreeMap::new();
-    for event in database.query(filter).await? {
+    for event in client.database().query(filter).await? {
         let Some(rumor_id) = event.tags.identifier() else {
             continue;
         };
@@ -297,21 +298,54 @@ pub async fn save_state(client: &Client, state: &CommunityState) -> Result<()> {
     Ok(())
 }
 
-pub async fn load_state<D>(database: &D, id: &CommunityId) -> Result<Option<CommunityState>>
-where
-    D: NostrDatabase + ?Sized,
-{
+pub async fn load_state(client: &Client, id: &CommunityId) -> Result<Option<CommunityState>> {
     let filter = Filter::new()
         .kind(Kind::ApplicationSpecificData)
         .identifier(state_identifier(id))
         .limit(1);
 
-    match database.query(filter).await?.into_iter().next() {
+    match client.database().query(filter).await?.into_iter().next() {
         Some(event) => Ok(Some(serde_json::from_str(&event.content)?)),
         None => Ok(None),
     }
 }
 
+/// The newest state document per community carried in the local database.
+pub async fn load_states(client: &Client) -> Result<Vec<CommunityState>> {
+    let filter = Filter::new().kind(Kind::ApplicationSpecificData);
+    let mut newest: BTreeMap<CommunityId, Event> = BTreeMap::new();
+
+    for event in client.database().query(filter).await? {
+        let Some(id) = state_document_of(&event) else {
+            continue;
+        };
+
+        match newest.get(&id) {
+            Some(existing) if existing.created_at >= event.created_at => {}
+            _ => {
+                newest.insert(id, event);
+            }
+        }
+    }
+
+    let mut states = Vec::with_capacity(newest.len());
+
+    for event in newest.into_values() {
+        match serde_json::from_str::<CommunityState>(&event.content) {
+            Ok(state) => states.push(state),
+            Err(error) => log::warn!("ignoring malformed community state {}: {error}", event.id),
+        }
+    }
+
+    Ok(states)
+}
+
+fn state_document_of(event: &Event) -> Option<CommunityId> {
+    let identifier = event.tags.identifier()?;
+    let hex = identifier.strip_prefix(STATE_PREFIX)?;
+    hex.parse().ok()
+}
+
 pub async fn backfill(
     client: &Client,
     channel: &ChannelId,
@@ -461,7 +495,11 @@ mod tests {
                 at_ms,
                 None,
             );
-            relay.insert(seal_rumor(&rumor, &group, &author, false).expect("seals").0);
+            relay.insert(
+                smol::block_on(seal_rumor(&rumor, &group, &author, false))
+                    .expect("seals")
+                    .0,
+            );
         }
 
         let mut seen = BTreeSet::new();
@@ -488,4 +526,43 @@ mod tests {
             ["after the rekey", "still before", "before the rekey"]
         );
     }
+
+    #[test]
+    fn load_states_reads_one_document_per_community_and_ignores_other_documents() {
+        smol::block_on(async {
+            let client = ClientBuilder::default()
+                .database(nostr_memory::MemoryDatabase::unbounded())
+                .build();
+
+            let state = CommunityState {
+                id: CommunityId::from_bytes([0x42; 32]),
+                owner: Keys::generate().public_key(),
+                owner_salt: [0x01; 32],
+                community_root: [0x02; 32],
+                root_epoch: Epoch(0),
+                control_root: None,
+                control_pks: BTreeMap::new(),
+                channels: Vec::new(),
+                relays: Vec::new(),
+                heads: Vec::new(),
+                banned: BTreeSet::new(),
+                dissolved: false,
+                added_at_ms: 7,
+            };
+
+            save_state(&client, &state).await.expect("saves");
+
+            // A cached rumor is also an application-specific document, but not a
+            // state document, so the prefix keeps it out of the state scan.
+            let other = EventBuilder::new(Kind::ApplicationSpecificData, "{}")
+                .tags([Tag::identifier("deadbeef")])
+                .finalize(&*LOCAL_KEYS)
+                .expect("builds");
+            client.database().save_event(&other).await.expect("saves");
+
+            let loaded = load_states(&client).await.expect("loads");
+
+            assert_eq!(loaded, vec![state]);
+        });
+    }
 }

crates/concord/src/utils/base64url.rs

@@ -0,0 +1,34 @@
+use anyhow::{Result, anyhow};
+use base64::engine::{DecodePaddingMode, GeneralPurpose, GeneralPurposeConfig};
+use base64::{Engine as _, alphabet};
+
+/// Unpadded base64url (RFC 4648 §5), 43 characters for 32 bytes: §8's value
+/// encoding at any depth.
+///
+/// The reader tolerates non-zero trailing bits; the writer never emits them.
+/// The spec's own worked example (`examples.md` §6.2) contains five such
+/// values, and a reader cannot tell a mis-encoded named field from a correctly
+/// encoded one, so the boundary is the writer's alone.
+const BASE64URL: GeneralPurpose = GeneralPurpose::new(
+    &alphabet::URL_SAFE,
+    GeneralPurposeConfig::new()
+        .with_encode_padding(false)
+        .with_decode_padding_mode(DecodePaddingMode::RequireNone)
+        .with_decode_allow_trailing_bits(true),
+);
+
+pub(crate) fn encode(bytes: &[u8]) -> String {
+    BASE64URL.encode(bytes)
+}
+
+/// Decodes one 32-byte value, the width every §8 field has.
+pub(crate) fn decode_32(value: &str) -> Result<[u8; 32]> {
+    let bytes = BASE64URL
+        .decode(value.trim())
+        .map_err(|error| anyhow!("invalid base64url: {error}"))?;
+
+    bytes
+        .as_slice()
+        .try_into()
+        .map_err(|_| anyhow!("expected 32 bytes, got {}", bytes.len()))
+}

crates/concord/src/utils/mod.rs

@@ -1,9 +1,13 @@
+pub mod base64url;
 pub mod derive;
 
 use anyhow::{Result, anyhow, bail};
 use data_encoding::HEXLOWER;
 use rand::TryRng as _;
 use rand::rngs::SysRng;
+use serde::Serialize;
+
+use crate::Extra;
 
 /// Uppercase and other non-canonical spellings are rejected.
 pub(crate) fn decode_hex_32(value: &str) -> Result<[u8; 32]> {
@@ -38,3 +42,34 @@ pub(crate) fn random_32() -> Result<[u8; 32]> {
     fill_random(&mut bytes)?;
     Ok(bytes)
 }
+
+/// Hex to unpadded base64url for one 32-byte §8 value.
+pub(crate) fn hex32_to_base64(value: &str) -> Result<String> {
+    Ok(base64url::encode(&decode_hex_32(value)?))
+}
+
+/// Unpadded base64url to lowercase hex for one 32-byte §8 value.
+pub(crate) fn base64_to_hex32(value: &str) -> Result<String> {
+    Ok(HEXLOWER.encode(&base64url::decode_32(value)?))
+}
+
+/// Canonical JSON bytes: the total-order tie-break every content merge uses.
+pub(crate) fn canonical<T: Serialize>(value: &T) -> String {
+    serde_json::to_string(value).unwrap_or_default()
+}
+
+/// Unions an unknown-field map. Where both sides carry a key, the
+/// lexicographically lowest canonical bytes win, so two devices converge
+/// instead of flapping.
+pub(crate) fn union(into: &mut Extra, other: Extra) {
+    for (key, value) in other {
+        let replace = match into.get(&key) {
+            Some(existing) => canonical(&value) < canonical(existing),
+            None => true,
+        };
+
+        if replace {
+            into.insert(key, value);
+        }
+    }
+}

crates/workspace/Cargo.toml

@@ -12,6 +12,7 @@ state = { path = "../state" }
 device = { path = "../device" }
 chat = { path = "../chat" }
 chat_ui = { path = "../chat_ui" }
+community = { path = "../community" }
 settings = { path = "../settings" }
 person = { path = "../person" }
 auto_update = { path = "../auto_update" }

crates/workspace/src/sidebar/mod.rs

@@ -5,9 +5,10 @@ use std::rc::Rc;
 use auto_update::AutoUpdater;
 use chat::{ChatEvent, ChatRegistry, Room, RoomKind};
 use common::TimestampExt;
+use community::{CommunityEvent, CommunityMetadata, CommunityRegistry};
 use gpui::prelude::FluentBuilder;
 use gpui::{
-    AnyElement, App, Context, ElementId, Entity, EventEmitter, FocusHandle, Focusable,
+    AnyElement, App, AppContext, Context, ElementId, Entity, EventEmitter, FocusHandle, Focusable,
     InteractiveElement, IntoElement, ParentElement, Render, SharedString, Styled, Subscription,
     UniformListScrollHandle, Window, div, px, retain_all, uniform_list,
 };
@@ -20,12 +21,13 @@ use ui::avatar::Avatar;
 use ui::button::{Button, ButtonVariants};
 use ui::dock::{Panel, PanelEvent};
 use ui::indicator::Indicator;
+use ui::input::{Input, InputState};
 use ui::menu::{ContextMenu, DropdownMenu, PopupMenuItem};
 use ui::nav_item::NavItem;
 use ui::scroll::Scrollbar;
 use ui::{
-    Icon, IconName, Sizable, StyledExt, TRAFFIC_LIGHT_PADDING, h_flex, title_bar_drag_handlers,
-    v_flex,
+    Icon, IconName, Sizable, StyledExt, TRAFFIC_LIGHT_PADDING, WindowExtension, h_flex,
+    title_bar_drag_handlers, v_flex,
 };
 
 use crate::Command;
@@ -34,7 +36,7 @@ mod entry;
 mod tree;
 
 pub(crate) use entry::RoomEntry;
-use tree::{SidebarRow, TreeRow, TreeRowKind, TreeSection, dummy_communities};
+use tree::{SidebarRow, TreeRow, TreeRowKind, TreeSection};
 
 /// Sidebar.
 pub struct Sidebar {
@@ -58,6 +60,7 @@ impl Sidebar {
     pub fn new(window: &mut Window, cx: &mut Context<Self>) -> Self {
         let settings = AppSettings::global(cx).read(cx).entity().clone();
         let chat = ChatRegistry::global(cx);
+        let communities = CommunityRegistry::global(cx);
 
         let mut subscriptions = smallvec![];
 
@@ -74,6 +77,14 @@ impl Sidebar {
             this.restore_state(cx);
         }));
 
+        subscriptions.push(
+            cx.subscribe(&communities, |_this, _communities, event, _cx| {
+                if let CommunityEvent::Error(error) = event {
+                    log::error!("community: {error}");
+                }
+            }),
+        );
+
         Self {
             focus_handle: cx.focus_handle(),
             scroll_handle: UniformListScrollHandle::new(),
@@ -145,6 +156,36 @@ impl Sidebar {
         self.pinned_rooms.contains(&room_id)
     }
 
+    fn new_community(&mut self, window: &mut Window, cx: &mut Context<Self>) {
+        let name_input = cx.new(|cx| InputState::new(window, cx).placeholder("Community name"));
+
+        window.open_modal(cx, move |this, _window, _cx| {
+            let name_input = name_input.clone();
+
+            this.width(px(380.))
+                .confirm()
+                .title("New community")
+                .child(Input::new(&name_input))
+                .on_ok(move |_event, _window, cx| {
+                    let name = name_input.read(cx).value().trim().to_owned();
+
+                    if name.is_empty() {
+                        return false;
+                    }
+
+                    let metadata = CommunityMetadata {
+                        name,
+                        ..CommunityMetadata::default()
+                    };
+
+                    CommunityRegistry::global(cx)
+                        .update(cx, |registry, cx| registry.create(metadata, cx));
+
+                    true
+                })
+        });
+    }
+
     fn tree_rows(&self, cx: &App) -> Vec<SidebarRow> {
         let chat = ChatRegistry::global(cx);
         let chat = chat.read(cx);
@@ -197,7 +238,9 @@ impl Sidebar {
             }
         }
 
-        let communities = dummy_communities();
+        let registry = CommunityRegistry::global(cx);
+        let communities = registry.read(cx).communities();
+
         rows.push(SidebarRow::Section {
             section: TreeSection::Community,
             count: communities.len(),
@@ -213,9 +256,15 @@ impl Sidebar {
                 rows.extend(
                     communities
                         .iter()
-                        .map(|entry| SidebarRow::Community { entry, depth: 1 }),
+                        .cloned()
+                        .map(|community| SidebarRow::Community {
+                            community,
+                            depth: 1,
+                        }),
                 );
             }
+
+            rows.push(SidebarRow::NewCommunity { depth: 1 });
         }
 
         let messages = chat.rooms(&RoomKind::Ongoing, cx);
@@ -345,13 +394,28 @@ impl Sidebar {
                         )
                         .into_any_element()
                     }
-                    SidebarRow::Community { entry, depth } => TreeRow::new(
+                    SidebarRow::Community { community, depth } => {
+                        let community = community.read(cx);
+
+                        TreeRow::new(
+                            ElementId::NamedInteger("tree-row".into(), index as u64),
+                            TreeRowKind::Community,
+                            community.name(),
+                        )
+                        .depth(*depth)
+                        .avatar(community.id().to_hex())
+                        .into_any_element()
+                    }
+                    SidebarRow::NewCommunity { depth } => TreeRow::new(
                         ElementId::NamedInteger("tree-row".into(), index as u64),
-                        TreeRowKind::Community,
-                        entry.name,
+                        TreeRowKind::Hint,
+                        "New community",
                     )
                     .depth(*depth)
-                    .avatar(entry.name)
+                    .icon(IconName::Plus)
+                    .on_click(cx.listener(|this, _event, window, cx| {
+                        this.new_community(window, cx);
+                    }))
                     .into_any_element(),
                     SidebarRow::Hint { text, depth } => TreeRow::new(
                         ElementId::NamedInteger("tree-row".into(), index as u64),

crates/workspace/src/sidebar/tree.rs

@@ -1,6 +1,7 @@
 use std::rc::Rc;
 
 use chat::Room;
+use community::Community;
 use gpui::prelude::FluentBuilder;
 use gpui::{
     App, ClickEvent, ElementId, Entity, InteractiveElement, IntoElement, ParentElement, RenderOnce,
@@ -66,7 +67,10 @@ pub enum SidebarRow {
         pinned: bool,
     },
     Community {
-        entry: &'static CommunityEntry,
+        community: Entity<Community>,
+        depth: u8,
+    },
+    NewCommunity {
         depth: u8,
     },
     Hint {
@@ -75,22 +79,6 @@ pub enum SidebarRow {
     },
 }
 
-pub struct CommunityEntry {
-    pub name: &'static str,
-}
-
-pub fn dummy_communities() -> &'static [CommunityEntry] {
-    // TODO(concord): replace with ConcordRegistry communities, see docs/concord-usage.md.
-    &[
-        CommunityEntry {
-            name: "Coop Contributors",
-        },
-        CommunityEntry {
-            name: "Nostr Design",
-        },
-    ]
-}
-
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum TreeRowKind {
     Section,

docs/concord-community-discovery-plan.md

@@ -0,0 +1,241 @@
+# Concord discovery: why no community ever reaches `subscribe`
+
+Audit + fix plan. Read alongside `docs/concord-usage.md` and
+`docs/concord-simplification-plan.md`.
+
+## Symptom
+
+`crates/community/src/lib.rs::subscribe` is never called, so no wrap is ever
+subscribed to and the sidebar stays empty. `community load: 0 state document(s)
+found` is the only clue.
+
+## Root cause
+
+`CommunityRegistry::load` only ever reads the **local database**. Nothing in the
+discovery path touches a relay.
+
+```
+community::init
+  └─ SignerChanged → load
+       └─ sync::load
+            ├─ store::load_states(client)   → client.database().query(..)   // local only
+            └─ load_list(client, ..)        → client.database().query(..)   // local only, .limit(1)
+       → track([])
+       → sync_subscriptions: `for community in self.communities` runs zero times
+       → subscribe never called
+       → no relay is ever queried
+       → the database never fills
+       → load stays empty forever
+```
+
+The loop is self-reinforcing: the local database is populated *by* the
+subscriptions that the empty load prevents. That is why an account which belongs
+to several communities in another client still shows nothing — a fresh install
+has no `concord/*` state document, and coop has no way to ask for one.
+
+Confirmed by inspection:
+
+| Location | What it does |
+| --- | --- |
+| `crates/community/src/lib.rs:167-191` | `load` → `sync::load`, then `track(states)` |
+| `crates/community/src/sync.rs:125-137` | `load` = `store::load_states` + `load_list` |
+| `crates/concord/src/store.rs:314-341` | `load_states` queries `client.database()` only |
+| `crates/community/src/sync.rs:139-153` | `load_list` queries `client.database()` only, `.limit(1)` |
+| `crates/community/src/lib.rs:233-276` | `sync_subscriptions` skips everything when `communities` is empty |
+
+`subscribe` itself is correct. Do not debug it.
+
+## What the protocol actually says
+
+Read from the spec (`concord-protocol/concord`, the submodule referenced by
+accordion.chat): `02.md` §8 and `examples.md` §6.2.
+
+A member's memberships live in the **Community List**, on relays:
+
+- **Kind `33302`**, addressable, NIP-44-encrypted to self, signed by the
+  member's real key, one event per **fragment** with `d` = the fragment index in
+  decimal (`"0"`, `"1"`, …). `13302` is explicitly **retired** ("the
+  single-event Community List, superseded by `33302` once it outgrew one event —
+  a replaceable kind cannot fragment", `02.md:314`).
+- Every 32-byte value at **any depth** is unpadded base64url, not hex. This is
+  section-scoped: CORD-05 invite fields stay hex (`examples.md` §6.3).
+- Join material is the membership subset — `owner, owner_salt, community_root,
+  root_epoch, control_pk, channels, relays, name`, plus `control_root` when
+  held. It is the *only* durable home of a member's keys.
+- The two snapshots solve opposite problems: `seed` is the earliest epoch held
+  (backfill anchor), `current` the latest ("so a fresh device reconstructs the
+  Community instantly with no epoch-by-epoch walk"). `seed` is omitted when
+  equal to `current`; embedded snapshots omit `community_id` (inherited).
+- A client holds the complete List when it holds a fragment at every index below
+  `frags`; it unions fragments and merges, so a partial read is safe.
+
+Two consequences for coop:
+
+1. **The state document is a coop invention.** `store::{save_state, load_state,
+   load_states}` write kind `30078` with `d = concord/<id>`, signed by a
+   per-process `LOCAL_KEYS`, and never leave the machine. No equivalent exists
+   anywhere in the spec. It is a local cache and must never be treated as the
+   discovery source.
+2. **Discovery is: fetch my `33302` from relays → materialize a community from
+   `current` join material → subscribe to its planes → fold.** The fold produces
+   the authoritative state; the List only supplies the keys to start.
+
+## Divergences (coop vs spec)
+
+| # | Spec | coop today |
+| --- | --- | --- |
+| 1 | kind `33302`, addressable | `cord02::list::KIND_COMMUNITY_LIST = 13302` (retired) |
+| 2 | one event per fragment, `d` = index, `frags` declared | no `frags`, single event, `d` unused, `load_list` `.limit(1)` |
+| 3 | 32-byte values unpadded base64url at any depth | hex: `JoinMaterial.owner`/`control_root` (`PublicKey`/`String`), `CommunityId` serde, `ChannelGrant.key` |
+| 4 | `seed` omitted when equal to `current`; embedded snapshot omits `community_id`; `seed`'s cosmetic fields rewritten from `current` | both snapshots always serialized verbatim; `community_id` always present |
+| 5 | fetch from relays | local database only |
+| 6 | materialize `CommunityState` from join material | no such path; only `CommunityState::from_genesis` |
+| 7 | publish the List on create/join (read-modify-write) | `build_list_event` is referenced only by tests and docs |
+| 8 | private channel keys ride in join material | `ChannelKeyRef` has no key field |
+
+Divergences 1–4 meant that even if the fetch existed, coop could neither read
+what accordion wrote nor write something accordion could read. **Phase A is
+done**, so 1–4 are resolved; 5–8 remain.
+
+## Plan
+
+Ordered so each phase is independently reviewable and testable. Nothing here
+touches the frozen HKDF derivations or `cord01` envelope semantics.
+
+### Phase A — make the List interoperable (pure, no I/O) — DONE
+
+`crates/concord/src/cords/cord02/list.rs`
+
+1. `KIND_COMMUNITY_LIST` → `33302`; add `frags: u64` to `CommunityList` and
+   `is_complete(&self, frags) -> bool`.
+2. Add a base64url codec for the §8 value set and apply it to every 32-byte
+   field at every depth. Because `JoinMaterial` currently types `owner` and
+   `control_pk` as `PublicKey` (nostr's hex serde), this needs either wire
+   newtypes or `serialize_with`/`deserialize_with` helpers. Keep it local to the
+   List: `cord05` stays hex.
+3. Implement the two §8 MUSTs: omit `community_id` on an embedded snapshot,
+   omit `seed` when it byte-equals `current`, and rewrite `seed`'s cosmetic
+   fields (`name`, `relays`, each channel's `name`) from `current` on every
+   serialization.
+4. `build_list_event`/`parse_list_event` take the fragment index and emit/read
+   the `d` tag.
+
+Tests: round-trip the `examples.md` §6.2 payload verbatim; `merge` convergence
+for two devices and mixed-age fragments; `frags` disagreement resolves to the
+larger value; a repack does not shed unknown fields.
+
+**As built.** The §8 rules live behind private wire structs (`WireList`,
+`WireEntry`, `WireSnapshot`, `WireChannel`), so a writer re-encodes on every
+serialization while the public types keep their internal hex/`PublicKey`
+spellings and `cord05` stays hex. Three deviations from the sketch above:
+
+- `is_complete` takes the set of fragment indices a client holds, not a count:
+  a count is wrong when the indices are sparse.
+- The reader tolerates non-zero base64url trailing bits. The spec's own §6.2
+example has five such values, so a strict decoder rejects the worked example;
+  the writer still emits the canonical spelling.
+- The third omission MUST was implemented too: an entry whose `added_at` does
+  not outrun its tombstone is not written. It is a serialization rule exactly
+  like the other two, so it belongs here rather than in Phase D.
+
+`parse_list_event` validates the `d` tag but returns just the `CommunityList`;
+`fragment_index(event)` reads the index, which keeps `sync.rs` untouched until
+Phase C. `MAX_MEMBERSHIPS = 50` is kept for now as a stopgap (see risks): §8 has
+no membership limit, and Phase D's fragmentation is what removes the cap.
+
+### Phase B — materialize a community from join material (pure)
+
+`crates/concord/src/store.rs`, `crates/concord/src/cords/cord02/list.rs`
+
+1. `CommunityState::from_join_material(material: &JoinMaterial, added_at_ms:
+   u64) -> Result<Self>`: identity/owner/salt/root/root_epoch from the material;
+   `control_pks = { root_epoch → control_pk }`; `relays` parsed; `channels` from
+   the grants; `control_root` when present; `heads` empty (the first control
+   fold fills them); `banned` empty; `dissolved` false.
+2. Carry the private channel key: add `key: Option<[u8; 32]>` to
+   `ChannelKeyRef` (or a parallel map) so a grant's `key` has a home. Without
+   this, a private channel is silently read-only-until-rekey.
+
+Tests: a material with and without `control_root`; a private grant's key
+survives; `from_join_material` then `planes()` yields the control `control_pk`
+plus the guestbook and public channels, i.e. a subscription filter that
+addresses real planes.
+
+### Phase C — fetch the List from relays, then load
+
+`crates/community/src/sync.rs`
+
+1. `load` becomes:
+   - resolve where to ask: the account's NIP-65 write relays (kind `10002`) plus
+     the pool's connected relays. If only the app's bootstrap relays are queried,
+     a List published by another client (e.g. accordion on `relay.damus.io` /
+     `nos.lol`) will simply not be found.
+   - `client.fetch_events(Filter::new().kind(33302).author(self_pk))` — one
+     filter returns every fragment. Fetched events are persisted by the client
+     (`nostr-sdk/src/relay/inner.rs:1291`), so the database read stays valid.
+   - merge fragments → `CommunityList`.
+   - for each entry whose `is_live(&id)`: if a state document exists, keep its
+     `heads` (the fold's authority) and refresh relays/keys from `current`;
+     otherwise `from_join_material(..)`.
+   - `store::save_state` each result so the next `load` is warm.
+2. `load_list` keeps reading `client.database()` — after the fetch it is
+   populated. It must stop using `.limit(1)`.
+3. Drop the `states.retain(..)` shape: the List is now the *source* of states,
+   not just a filter over local ones. A local state whose membership is
+   tombstoned is still dropped, but a List entry with no local state now
+   produces one.
+
+Tests (no network, `nostr-memory`): a `33302` fragment written by the account is
+discovered with **no** state document present; a tombstoned id is dropped; a
+missing fragment leaves the rest usable. A `nostr_sdk::local_relay::LocalRelay`
+(in-process relay, public in this pinned revision) can drive the real
+fetch/subscribe path end to end.
+
+### Phase D — publish
+
+`crates/community/src/sync.rs`, `crates/concord/src/store.rs`
+
+1. `create` appends to the List and publishes the fragment read-modify-write per
+   §8, targeting the metadata's relays.
+2. `create` publishes the genesis wraps to those relays. Today it only
+   `client.database().save_event(wrap)`s, so a created community is invisible to
+   every other account.
+3. Leave uses a tombstone; a repack requires the complete List and is a
+   non-goal until memberships outgrow one fragment.
+
+### Phase E — verify live
+
+`RUST_LOG=info cargo run -p coop`, sign in with the accordion account that
+already belongs to communities. Expect `community {id}: subscribing to ..` and
+rows in the sidebar. This is the first time the path can be exercised at all.
+
+## Validation per phase
+
+- `cargo test -p concord` (A, B), `cargo test -p community` (B, C, D).
+- `cargo clippy --workspace --all-targets`, `cargo fmt --all -- --check`.
+- A is provable against the spec's worked example, so it needs no relay.
+- C is provable with `nostr-memory` + `LocalRelay`, so it needs no network.
+- E is the only step that needs real relays.
+
+## Risks and open decisions
+
+- **Base64url is case-significant and coop's ids are hex everywhere else.**
+  Confine the codec to `cord02::list`; any normalisation that case-folds will
+  silently corrupt §8 values. **Resolved in Phase A**: the codec is private to
+  `list.rs` and never case-folds.
+- **`MAX_MEMBERSHIPS = 50` is not in the spec.** §8 has no membership limit; its
+  only bound is the 65,536-byte *encoded event*. `fits()` still measures the
+  NIP-44 plaintext, which understates that by roughly a third, so the count cap is
+  kept as a conservative stopgap until Phase D measures the built event and
+  fragments on write.
+- **Relay selection for the fetch is the difference between finding the account's
+  List and not.** NIP-65 write relays + pool, or a user-visible relay setting?
+- **Private channels stay unreadable until `ChannelKeyRef` carries the grant key**
+  (Phase B.2). Public discovery works without it.
+- **Two writers, one key.** Once coop publishes `33302`, an account used from
+  both accordion and coop has both clients writing the List. §8's
+  read-modify-write is what keeps that from losing memberships — it is not
+  optional.
+- **`store::save_state` signs with a per-process random key.** Harmless while it
+  stays local, but it means the state document can never be published or
+  compared; if a future phase wants it on the wire, it needs the account signer.

docs/concord-simplification-plan.md

@@ -0,0 +1,358 @@
+# Concord backend audit and simplification plan
+
+Audit of `crates/concord`, triggered by `CommunityRegistry` never reaching
+`subscribe`: `sync::load` found zero community state documents. Tracing that
+surfaced two separate things: the app only uses a fraction of the crate, and the
+crate's writers take a concrete `nostr::Keys`, which the app's signer can never
+produce.
+
+Sizes: ~10,500 lines total — ~6,750 production, ~3,750 tests.
+
+## Decisions taken
+
+- **D1 — Keep the unwired protocol surface.** `cord05`/`cord06`/`pins`/paging
+  stay in the tree for future use. No mass deletion. (Findings are recorded in
+  §4 for reference only.)
+- **D2 — Replace `&Keys` with a signer boundary** for account-key operations.
+  Verified feasible against the pinned SDK; design in §2.
+
+---
+
+## 1. `&Keys` cannot be replaced by a public key — but it can be replaced by a signer
+
+The original question was whether functions like `genesis` only need
+`signer.get_public_key_async()`. They do not: they sign.
+
+- `cord02::genesis` (`cords/cord02/mod.rs:117`) → `seal_edition` (`:711`) →
+  `build_seal` (`cord01.rs:217`), which signs the seal (`.finalize(author)`,
+  `cord01.rs:226`), and `wrap_seal_with` (`:247`), which signs the wrap.
+- Self-addressed documents use NIP-44 to self: `seal_to_self`
+  (`cord01.rs:201`) derives a conversation key from `keys.secret_key()`.
+
+A public key can produce neither a Schnorr signature nor an ECDH key, so
+"public-key-only" is impossible. The real defect is the **concrete type**: the
+app holds `state::UniversalSigner` (async, possibly NIP-46), and a `nostr::Keys`
+can never be conjured from it. `docs/concord-usage.md:535-536` already records
+this as a deliberate migration pass.
+
+### What the pinned SDK actually provides
+
+Pinned rev `b230cec` (`nostr` 0.45.4 / `nostr-sdk` 0.45.2):
+
+- There is **no `NostrSigner` trait in this revision.** The async signer surface
+  is three traits, all in the `nostr` crate:
+  - `AsyncGetPublicKey` — `nostr/src/key/public_key.rs:39`
+  - `AsyncSignEvent` — `nostr/src/event/mod.rs:366`
+  - `AsyncNip44` — `nostr/src/nips/nip44/traits.rs:30`
+- `Keys` implements all three (`nostr/src/key/mod.rs:298,309,342`), so tests and
+  local key holders keep working.
+- `UniversalSigner` already implements all three with
+  `Error = UniversalSignerError` (`crates/state/src/signer.rs:148-191`).
+- SDK helpers accept them:
+  - `EventBuilder::finalize_async` — `S: AsyncGetPublicKey + AsyncSignEvent + ?Sized`
+    (`nostr/src/event/builder.rs:171-193`)
+  - `GiftWrapBuilder::finalize_async` — `S: AsyncGetPublicKey + AsyncSignEvent + AsyncNip44`
+    (`nostr/src/nips/nip59.rs:334-355`)
+  - `UnwrappedGift::from_gift_wrap_async` — `T: AsyncNip44` (`nip59.rs:84-90`)
+
+So the answer is yes: pass a signer. `UniversalSigner` works as-is.
+
+### Per-function bounds, not a bundle
+
+Each function should request only the capabilities it uses. The SDK itself is
+designed this way (`UnsignedEvent::finalize_async` takes only `AsyncSignEvent`,
+`EventBuilder::finalize_async` takes `AsyncGetPublicKey + AsyncSignEvent`,
+NIP-59 takes all three).
+
+| Operation | Bounds |
+| --- | --- |
+| Sign a seal/edition/rekey wrap, author already known | `AsyncSignEvent` |
+| Build an event where the author comes from the signer | `AsyncGetPublicKey + AsyncSignEvent` |
+| To-self documents (Community List, Invite List) | `AsyncGetPublicKey + AsyncNip44`, plus `AsyncSignEvent` when the document is itself an event |
+| Decrypt-only (`parse_list_event`, `unwrap_direct_invite`) | `AsyncNip44` |
+| Rekey blob encrypt (`build_blob`) | `AsyncGetPublicKey + AsyncNip44` (no signing) |
+| Rekey blob open (`open_blob`) | `AsyncNip44` |
+| Direct invite build (`GiftWrapBuilder`) | all three |
+
+Use generics (`S: AsyncSignEvent + ?Sized`), never `&dyn`: the traits carry
+associated `Error` types, so `dyn AsyncSignEvent` would force the concrete error
+at every call site (`dyn AsyncSignEvent<Error = UniversalSignerError>`),
+defeating the abstraction. The SDK uses generics throughout for this reason.
+
+Do **not** define a supertrait bundle
+`trait Signer: AsyncGetPublicKey + AsyncSignEvent + AsyncNip44 {}`: all three
+supertraits declare an associated `Error`, so `Self::Error` becomes ambiguous,
+and the bundle forces NIP-44 onto purely-signing callers (and vice versa).
+
+Inside concord, replace `builder.finalize(&keys)` with
+`builder.finalize_async(signer).await`. `finalize_async` fetches the signer's
+public key and uses it as the event author, exactly as `finalize` did, so the
+bytes are unchanged for every caller that passes a matching signer.
+
+We deliberately **do not** pre-check the author against `rumor.pubkey` inside
+`build_seal`. The seal's author is the signer's own public key, matching the old
+`finalize` semantics; a signer that does not match the rumor is still caught by
+`open_wrap_at` as `AuthorMismatch` (`cord01.rs:328`). Pre-checking would also
+make it impossible to construct the hostile seals the cord suite relies on as
+test vectors (`cord01.rs` `hostile_wraps_are_dropped_in_order`).
+
+If the repeated `<S as ...>::Error: Error + Send + Sync + 'static` bounds
+become too noisy, the only stable-Rust way to shorten them is an owned
+error-erased trait (as the app already does with
+`crates/state/src/signer.rs:64-138`). That trades precision for brevity; keep
+per-function bounds unless the noise proves unmanageable.
+
+### What must NOT go through the signer
+
+- **Group-key NIP-44.** `cord01::{seal_bytes, open_bytes, wrap_seal,
+  wrap_seal_with, rewrap_seal}` encrypt under a `ConversationKey` derived from
+  HKDF group secrets. `AsyncNip44` can only ECDH against a public key, so group
+  encryption stays on `ConversationKey` / `GroupKey::keys()`.
+- **Wrap signatures.** Wraps are signed by the derived group signer key
+  (`GroupKey::keys()`), not the account.
+- **Locally held raw secrets.** `cord05::{build_bundle_event, build_revocation}`
+  take a generated `link_signer` whose secret the app stores as
+  `signer_sk` (`docs/concord-usage.md:306-321`). `&Keys` is correct there; the
+  app has the secret itself.
+- **Local database artifacts.** `store::{cache_rumor, save_state}` sign with the
+  internal random `LOCAL_KEYS` (`store.rs:18`). No user signer involved.
+
+### Call-site inventory
+
+Account-key sites to migrate:
+
+| Site | Today | After | Bounds |
+| --- | --- | --- | --- |
+| `cord02::genesis` (`cord02/mod.rs:117`) | `owner: &Keys` | `owner: &S` | `AsyncGetPublicKey + AsyncSignEvent` |
+| `ControlWriter::{publish, set_*}` (`cord02/mod.rs:214-425`) | `keys: &Keys` | `keys: &S` | `AsyncGetPublicKey + AsyncSignEvent` |
+| `seal_edition` (`cord02/mod.rs:711`, internal) | `owner: &Keys` | `owner: &S` | `AsyncGetPublicKey + AsyncSignEvent` |
+| `cord01::build_seal` (`cord01.rs:217`) | `author: &Keys` | `author: &S` | `AsyncGetPublicKey + AsyncSignEvent` |
+| `cord01::{seal_to_self, open_to_self}` (`:201,209`) | `keys: &Keys` | `&S`, async | `AsyncGetPublicKey + AsyncNip44` |
+| `guestbook::seal_rumor` (`guestbook.rs:186`) | `author: &Keys` | `author: &S` | `AsyncGetPublicKey + AsyncSignEvent` |
+| `cord03::seal_rumor` (`cord03.rs:295`) | `author: &Keys` | `author: &S` | `AsyncGetPublicKey + AsyncSignEvent` |
+| `list::build_list_event` (`list.rs:186`) | `keys: &Keys` | `keys: &S` | all three |
+| `list::parse_list_event` (`list.rs:197`) | `keys: &Keys` | `keys: &S` | `AsyncGetPublicKey + AsyncNip44` |
+| `cord05::{build_direct_invite, unwrap_direct_invite}` (`:451,478`) | `inviter`/`recipient: &Keys` | **done** | build: all three (`Sized`); unwrap: `AsyncNip44` (`Sized`) |
+| `cord05::{build_invite_list, parse_invite_list}` (`:593,604`) | `keys: &Keys` | **done** | build: all three; parse: `AsyncGetPublicKey + AsyncNip44` |
+| `cord06::build_blob` (`:302`) | `rotator: &Keys` | **done** | `AsyncGetPublicKey + AsyncNip44` |
+| `cord06::open_blob` (`:319`) | `recipient: &Keys` | **done** | `AsyncNip44` |
+| `cord06::{build_rekey_chunks, seal_dissolved}` (`:602,737`) | actor `&Keys` | **done** | `AsyncGetPublicKey + AsyncSignEvent` |
+
+Leave unchanged: `cord05::{build_bundle_event, build_revocation}`, all
+`cord01` wrap functions, `GroupKey::keys()`, `store::LOCAL_KEYS`.
+
+### Async ripple and tests
+
+Every migrated function becomes `async`. `smol` is already a dev-dependency of
+concord (`crates/concord/Cargo.toml:21-23`), so affected `#[test]`s become
+`smol::block_on(...)` wrappers. The app's call sites are already async
+background tasks.
+
+### Known constraints
+
+- `GiftWrapBuilder::finalize_async` and `UnwrappedGift::from_gift_wrap_async`
+  are generic over `S: Sized` (no `?Sized`), so those functions must stay
+  generic, never `&dyn`.
+- Every converted `S::Error` must be `Error + Send + Sync + 'static` for the
+  SDK helpers' `Error::other` (`nostr/src/error.rs:100-105`) and for
+  `anyhow`; `Keys::AsyncGetPublicKey::Error = Infallible`,
+  `Keys::AsyncSignEvent::Error = nostr::Error`, `UniversalSignerError`
+  (`crates/state/src/signer.rs:10-32`) all qualify.
+- `AsyncGetPublicKey` is worth requiring alongside `AsyncSignEvent` wherever the
+  author is embedded in the payload: `sign_event` signs the id of the given
+  unsigned event without rewriting its pubkey, so a mismatched signer is only
+  caught later by signature verification.
+
+---
+
+## 2. Migration plan
+
+### Phase 1 — replace `&Keys` with per-function signer bounds (no behavior change) — DONE
+
+1. No new module: change the signatures listed in the inventory table to
+   generics over the SDK traits (`S: AsyncGetPublicKey + AsyncSignEvent`,
+   `S: AsyncSignEvent`, `S: AsyncGetPublicKey + AsyncNip44`, or `S: AsyncNip44`).
+2. Migrate the live path only: `cord01::build_seal`, `cord01::{seal_to_self,
+   open_to_self}`, `seal_edition`, `genesis`, `ControlWriter`, `guestbook::
+   seal_rumor`, `cord03::seal_rumor`, `list::{build,parse}_list_event`.
+3. Update `docs/concord-usage.md` examples to take a signer.
+4. Update concord tests to `smol::block_on`; `&Keys` keeps working because it
+   implements all three traits.
+
+Validation: `cargo test -p concord` — 46 passed, 0 failed. The one behavior
+change from the plan sketch is the dropped up-front author check in §1.
+`cord01::{seal_to_self, open_to_self}` now take `&str` and return `String`
+(NIP-44 is UTF-8 text), so the `list` and invite-list callers read the plaintext
+with `serde_json::from_str`.
+
+**Unplanned but forced:** `cord01::{build_seal, seal_to_self, open_to_self}` are
+shared helpers, so the unwired callers had to be migrated in the same pass to
+keep the crate compiling: `cord05::{build_invite_list, parse_invite_list}` and
+`cord06::{build_rekey_chunks, seal_dissolved}` (Phase 3's mechanical part).
+`cord05::{build_direct_invite, unwrap_direct_invite}` and
+`cord06::{build_blob, open_blob}` were untouched by Phase 1 — they use the NIP-59
+and group-key paths, not the migrated helpers — and were migrated in Phase 3.
+
+### Phase 2 — app uses the signer — DONE
+
+1. `sync::create(client, signer, metadata)` (`crates/community/src/sync.rs`) runs
+   `cord02::genesis`, opens the genesis editions, persists the state with
+   `store::save_state`, and also stores the genesis wraps so the control plane
+   folds locally. It is generic over `S: AsyncGetPublicKey + AsyncSignEvent + ?Sized`
+   (the bounds `genesis` needs and no more, per D2); the app passes its
+   `UniversalSigner`, so no secret material is exposed and NIP-46 accounts work
+   too.
+   `CommunityRegistry::create(metadata, cx)` (`crates/community/src/lib.rs`) is
+   the GPUI wrapper: it refuses when no account is signed in, otherwise runs the
+   task off-thread and refreshes tracking, so `sync::load` now returns one state
+   and `subscribe` finally fires.
+2. The app-side reimplementation of `list::parse_list_event`
+   (`crates/community/src/sync.rs:154-156`) is deleted; `load_list` calls the
+   real `cord02::list::parse_list_event`.
+3. Relays in the metadata are persisted but the genesis is **not** published yet;
+   `create` is local-only. Wiring genesis/broadcast through the relay pool is the
+   next app step, not part of this phase.
+
+Validation: `cargo test -p community` (1 passed), `cargo test -p concord`
+(46 passed), `cargo clippy -p community --all-targets`, `cargo fmt -p community
+--check`, and `cargo check --workspace --all-targets` are all clean.
+
+**Deviation from the plan sketch:** the planned "drive `CommunityRegistry`" test
+is instead a `sync`-layer test, `sync::tests::
+creating_a_community_persists_a_state_that_subscribes_and_folds`. A GPUI-level
+test cannot construct a `NostrRegistry` — it opens LMDB at `config_dir()` and
+connects bootstrap relays in `NostrRegistry::new`, which is private and not
+injectable — so the test drives a `Client` on an in-memory database
+(`nostr-memory`, already a dev-dependency) directly. It asserts the whole
+contract the registry depends on: `create` persists a state `load` returns, the
+subscription filter addresses the genesis wraps, `fold` yields the created
+community, and an inbound control edit folds over it.
+
+### Phase 3 — migrate the remaining unwired writers — DONE
+
+`cord05::{build_direct_invite, unwrap_direct_invite}` and
+`cord06::{build_blob, open_blob}` now take a signer. The NIP-59 pair keeps a
+`Sized` `S` (`AsyncGetPublicKey + AsyncSignEvent + AsyncNip44` to build,
+`AsyncNip44` to unwrap) because the SDK's `GiftWrapBuilder::finalize_async` and
+`UnwrappedGift::from_gift_wrap_async` are `Sized`-bounded. The blob pair is
+`AsyncGetPublicKey + AsyncNip44` to build and `AsyncNip44` to open, with `?Sized`.
+
+The blobs forced one behavior change, because a signer's NIP-44 is text-only
+(`nip44_encrypt_async(public_key, &str)`) while the blob plaintext is a
+fixed-width binary record. `build_blob` now carries that record base64-encoded
+inside the NIP-44 envelope and `open_blob` decodes it again. The record layout,
+the `locator`, and the envelope are unchanged; only the bytes inside the envelope
+differ. There are no golden vectors for blobs and no producer or consumer other
+than these two functions, so the round-trip stays self-consistent; cord06 remains
+unwired and persists nothing.
+
+Validation: `cargo test -p concord` — 46 passed, 0 failed (the 80-blob
+`a_full_send_chunk_stays_within_a_relay_event` size assertion still holds under
+the base64 record). `cargo clippy -p concord --all-targets` and
+`cargo fmt -p concord --check` are clean.
+
+### Phase 4 — duplication and hygiene (independent, low risk) — DONE
+
+1. DONE — `store::load_states(client)` added (with a direct `store` test), the
+   app-side state-document scan in `sync::load` is gone.
+2. DONE — `store::STATE_PREFIX` is public; the app-side `concord/` literals are
+   gone, and subscription ids reuse the exported prefix.
+3. DONE — the shared rumor tag readers and error live in a new `cords::rumor`
+   module (`RumorError`, `tag`, `required`, `value`, `pubkey`,
+   `optional_citation`), re-exported as `cord03::ChatError` and
+   `cord02::guestbook::GuestbookError`. `cord06` keeps its own narrower
+   `RekeyError`, which the plan scoped out.
+4. RETAINED — none of the "never-varied parameters" were removed. Each is
+   load-bearing for a flow the fold or a writer already implements (D1):
+   - `complete_memberlist`'s `banned_at` is read by the fold and is exercised
+     with a non-empty map by `join_leave_kick_and_snapshot_converge_to_one_memberlist`;
+     `docs/concord-usage.md` already promises to fill it once the banlist head's
+     timestamp is plumbed through.
+   - `cache_rumor -> Result<bool>` is read by `backfill` to drop expired rumors.
+   - `coalesce`'s `snapshot_authority` gates which snapshots apply; passing
+     `None` today is a policy, not a dead parameter.
+   - `seal_rumor(ephemeral)` and the `until` cursors on `backfill`/`query_rumors`
+     select protocol modes and paging.
+5. DONE — tightened `cord04` visibility: `edition_hash`, `fold`, `FoldResult`,
+   `bootstrap_head`, `parse_banlist`, `Role::parse` and `Grant::parse` are no
+   longer `pub`. `HeadSelection` stays `pub` because the public `fold_head`
+   returns it.
+6. DONE — doc drift fixed: the store takes `&Client` throughout (including
+   `load_state`/`load_states`/`query_rumors`, not just the writers), `backfill`
+   arity, `set_pin_list`'s missing `.await`, the GPUI `init` signature and
+   registry names, and the "Not wired up yet" registry bullet.
+
+### Phase 5 — sidebar calls `create` — DONE
+
+The last blocker was that nothing invoked `CommunityRegistry::create`; the
+running app logged `community load: 0 state document(s) found` and `subscribe`
+never ran. The sidebar now:
+
+1. Renders `CommunityRegistry::communities()` instead of the hardcoded
+   `dummy_communities()`. `SidebarRow::Community` carries an `Entity<Community>`,
+   labelled with `Community::name()` (control-fold metadata, falling back to the
+   community id until the first fold).
+2. Adds a "New community" row to the Community section that opens a name prompt
+   and calls `CommunityRegistry::create` with default metadata. Relays stay empty,
+   so the subscription resolves through `ReqTarget::auto` against the pool's
+   relays rather than a manual target that `add_relay` might not have connected.
+3. Observes the registry, so a `track` or fold re-render reaches the list, and
+   subscribes to `CommunityEvent::Error`, which is now logged
+   (`log::error!("community: {error}")`) instead of vanishing. A `cx.notify()` in
+   the registry's per-community observer propagates the fold that fills in the
+   name.
+
+Validation: `cargo check -p workspace -p community --all-targets`,
+`cargo test -p community` (1 passed), `cargo clippy -p workspace -p community
+--all-targets`, and `cargo fmt -p workspace -p community --check` are clean.
+
+Still local-only: the genesis is persisted but not published to relays, so a
+second account cannot discover the community yet.
+
+---
+
+## 3. Retained-by-decision surface (reference only)
+
+Per D1 these stay, but they should be understood as unwired, not live:
+
+| Module | Approx. prod LOC | App use |
+| --- | --- | --- |
+| `cord06` rotation/refounding/dissolution | ~850 | none |
+| `cord05` invites/links/direct/list | ~650 | none (types only, via unused `list::join_material`) |
+| `cord04::pins` | ~550 | none |
+| `cord03` write path + `fold` + `plane_keys` | ~340 | only `open` / `expiration_of` |
+| guestbook / list write paths | ~240 | `open`, `coalesce`, `complete_memberlist`, `is_live` |
+| `store` paging / purge / query / load_state(s) | ~180 | `cache_rumor`, `save_state`, `load_states` |
+
+Truly unreferenced even by tests (safe candidates, but kept per D1):
+`CommunityInvite::expired`, `GroupKey::pk_hex`, `From<[u8; 32]>` impls,
+`CommunityRoles::{roles, is_empty}`.
+
+---
+
+## 4. Non-goals
+
+- No mass deletion of unwired modules (D1).
+- No changes to frozen HKDF derivations, locators, golden vectors, or `cord01`
+  envelope semantics. The one exception Phase 3 forced is the blob plaintext
+  encoding (base64 inside the envelope, see Phase 3); the blob record layout and
+  `locator` are untouched.
+- No group-key encryption through the signer.
+- Tests move only alongside the code they cover.
+
+## 5. Validation
+
+- `cargo test -p concord` after each phase; `cargo test --workspace` before
+  landing.
+- Phase 1 is behavior-preserving: the existing cord test suite is the oracle.
+- Phase 2 adds the app-level test: seed a `CommunityState` via
+  `store::save_state`, drive `CommunityRegistry`, assert a subscription is made
+  and an inbound wrap folds into the community.
+- Phase 4: `cargo test -p concord -p community` (47 + 1 passed),
+  `cargo clippy -p concord -p community --all-targets`, and
+  `cargo fmt -p concord -p community --check` are all clean.
+
+## 6. Immediate unblock
+
+Option 2 (the clean path, using `UniversalSigner`) landed in Phase 2. Option 1
+(exposing the local `Keys` from `crates/state/src/lib.rs:254`) is obsolete.

docs/concord-usage.md

@@ -47,7 +47,7 @@ use concord::cord02::{self, CommunityMetadata};
 use concord::store::{self, CommunityState, save_state};
 
 let metadata = CommunityMetadata { name: "Room".into(), ..Default::default() };
-let minted = cord02::genesis(&owner_keys, &metadata, now_secs)?;
+let minted = cord02::genesis(&owner_keys, &metadata, now_secs).await?;
 
 // minted.identity    — community_id, owner, owner_salt (verify() recomputes it)
 // minted.wraps       — the two owner-signed genesis editions, already sealed
@@ -73,7 +73,7 @@ let editions: Vec<ParsedEdition> = minted
     .collect::<Result<_, _>>()?;
 
 let mut state = CommunityState::from_genesis(&minted, &editions, added_at_ms)?;
-save_state(database, &state).await?;
+save_state(&client, &state).await?;
 ```
 
 Put the community's relay list into `state.relays` and add those relays to the
@@ -98,7 +98,7 @@ let invite = match cord05::parse_bundle_event(&event, &link.link_signer, &invite
 A Direct Invite arrives as a NIP-59 gift wrap addressed to the member:
 
 ```rust
-let (inviter, invite) = cord05::unwrap_direct_invite(&wrap, &my_keys)?;
+let (inviter, invite) = cord05::unwrap_direct_invite(&wrap, &my_keys).await?;
 ```
 
 Either way the invite carries `community_id`, `owner`, `owner_salt`,
@@ -114,7 +114,7 @@ use concord::cord02::guestbook;
 
 let guestbook = guestbook_group_key(&invite.community_root, &invite.community_id, invite.root_epoch)?;
 let rumor = cord02::guestbook::build_join(my_pk, Some((creator_npub, label)), now_ms);
-let (wrap, _) = cord02::guestbook::seal_rumor(&rumor, &guestbook, &my_keys)?;
+let (wrap, _) = cord02::guestbook::seal_rumor(&rumor, &guestbook, &my_keys).await?;
 client.send_event(&wrap).to(&relays).await?;
 ```
 
@@ -159,7 +159,7 @@ use concord::derive::channel_group_key;
 
 let plane = channel_group_key(&community_root, &channel, epoch)?;   // public channel
 let rumor = build_message(my_pk, &channel, epoch, text, None, at_ms, timer);
-let (wrap, wrap_key) = cord03::seal_rumor(&rumor, &plane, &my_keys, false)?;
+let (wrap, wrap_key) = cord03::seal_rumor(&rumor, &plane, &my_keys, false).await?;
 client.send_event(&wrap).to(&relays).await?;
 ```
 
@@ -192,7 +192,7 @@ for wrap in &wraps {
     let Ok((opened, rumor)) = cord03::open(wrap, group, &channel, *epoch) else {
         continue;
     };
-    store::cache_rumor(database, &channel, &opened).await?;
+    store::cache_rumor(&client, &channel, &opened).await?;
     rumors.push(rumor);
 }
 
@@ -209,13 +209,13 @@ let messages = fold(&rumors, Timestamp::now(), |actor, citation, author| {
 Relay history pages through the local cache:
 
 ```rust
-let page = store::backfill(client, database, &channel, &held, until, 50).await?;
-let cached = store::query_rumors(database, &channel, None, 50).await?;
+let page = store::backfill(client, &channel, &held, until, 50).await?;
+let cached = store::query_rumors(&client, &channel, None, 50).await?;
 ```
 
 `backfill` walks newest-first across every held epoch, caches what it opens, and
 stops on a short page. `query_rumors` is the read path when the group keys are
-gone. Run `store::purge_expired(database, &channel, now)` on the same cadence as
+gone. Run `store::purge_expired(client, &channel, now)` on the same cadence as
 any other local sweep — the timer is cooperative, so the local store is the
 artifact that has to forget.
 
@@ -253,7 +253,7 @@ let writer = ControlWriter { author: my_pk, read: read.clone(), signer: signer.c
 let head = control.floors.get(entity).cloned();
 
 let (wrap, new_head) = writer.set_community_metadata(
-    &my_keys, &community_id, &metadata, head.as_ref(), citation, now_secs)?;
+    &my_keys, &community_id, &metadata, head.as_ref(), citation, now_secs).await?;
 ```
 
 `citation` is the `vac` the actor acts under — `None` only for the owner. Build it
@@ -275,7 +275,7 @@ let head_content = control.pin_content(&community_id, &channel).unwrap_or("");
 let read = cord04::pins::read_list(head_content, |epoch| channel_group_key(&root, &channel, epoch).ok());
 let content = cord04::pins::publishable(&read, channel_is_private, &plane, epoch)?;
 let (wrap, _) = writer.set_pin_list(
-    &my_keys, &community_id, &channel, &content, head, citation, now_secs)?;
+    &my_keys, &community_id, &channel, &content, head, citation, now_secs).await?;
 ```
 
 Reading is verification: `read_list` decodes either content form (public, or
@@ -308,7 +308,7 @@ keep it against the token in the member's own Invite List — a local document
 encrypted to self, exactly like the Community List:
 
 ```rust
-let mut list = cord05::parse_invite_list(&my_keys, &event)?;
+let mut list = cord05::parse_invite_list(&my_keys, &event).await?;
 list.entries.push(InviteEntry {
     token: HEXLOWER.encode(&token),
     signer_sk: link_signer.secret_key().to_secret_hex(),
@@ -319,7 +319,7 @@ list.entries.push(InviteEntry {
     expires_at: None,
     extra: Default::default(),
 });
-let event = cord05::build_invite_list(&my_keys, &list)?;      // kind 13303
+let event = cord05::build_invite_list(&my_keys, &list).await?;      // kind 13303
 
 // Retiring is a tombstone, never a deletion: it beats a stale copy terminally.
 list.tombstones.push(InviteTombstone {
@@ -356,12 +356,16 @@ let (control_pk, control_root) = match scope {
     RekeyScope::Channel(_) => (None, None),
 };
 
-let blobs = members
-    .iter()
-    .map(|member| {
-        cord06::build_blob(&my_keys, member, scope, plan.epoch, &new_key, control_pk.as_ref(), control_root)
-    })
-    .collect::<Result<Vec<_>, _>>()?;
+let mut blobs = Vec::with_capacity(members.len());
+
+for member in &members {
+    blobs.push(
+        cord06::build_blob(
+            &my_keys, member, scope, plan.epoch, &new_key, control_pk.as_ref(), control_root,
+        )
+        .await?,
+    );
+}
 
 let rekey_group = cord06::rekey_group(scope, &community_root, &community_id, plan.epoch)?;
 let wraps = cord06::build_rekey_chunks(
@@ -375,7 +379,8 @@ let wraps = cord06::build_rekey_chunks(
     citation,
     false,
     now_secs,
-)?;
+)
+.await?;
 ```
 
 On the receiving side, `cord06::parse_rekey_chunk(&opened)` per wrap, then
@@ -385,11 +390,15 @@ member finds their delivery with `find_my_blobs` / `open_blob`, and adopts the k
 only if the plaintext binds to the scope and epoch they expect and its `prevcommit`
 matches the key they already hold. Two concurrent rotations settle on `fork_winner`.
 
+The blob plaintext is a fixed-width binary record, but a signer's NIP-44 is
+text-only, so `build_blob` carries it base64-encoded inside the envelope.
+`open_blob` mirrors that, so the record layout and the `locator` are unchanged.
+
 Dissolution is owner-only and terminal:
 
 ```rust
 let rumor = cord06::dissolved_tombstone_rumor(owner_pk, &community_id, now_secs);
-let wrap = cord06::seal_dissolved(&rumor, &community_id, &my_keys, now_secs)?;
+let wrap = cord06::seal_dissolved(&rumor, &community_id, &my_keys, now_secs).await?;
 
 // A receiver seals the community read-only on sight.
 if cord06::verify_dissolved(&wrap, &identity) {
@@ -404,22 +413,52 @@ A member's own memberships, synced across their devices:
 ```rust
 use concord::cord02::list;
 
-let material = cord02::list::join_material(&invite, staff.then_some(&control_root));
-let mut mine = cord02::list::parse_list_event(&my_keys, &event)?;
-mine = cord02::list::merge(mine, cord02::list::CommunityList {
-    entries: vec![cord02::list::CommunityListEntry { community_id, seed: material.clone(), current: material, added_at: now_ms, extra: Default::default() }],
-    ..Default::default()
+let material = list::join_material(&invite, staff.then_some(&control_root));
+let mut mine = list::parse_list_event(&my_keys, &event).await?;   // validates the d tag
+mine = list::merge(mine, list::CommunityList {
+    entries: vec![list::CommunityListEntry { community_id, seed: material.clone(), current: material, added_at: now_ms, extra: Default::default() }],
+    ..Default::default()                                          // frags: 1
 });
-let event = cord02::list::build_list_event(&my_keys, &mine)?;      // kind 13302, NIP-44 to self
+let event = list::build_list_event(&my_keys, &mine, 0).await?;   // kind 33302, d = fragment 0
 ```
 
+Kind `33302` is **addressable and fragmented**: one event per fragment, its `d`
+tag the fragment index in decimal. `frags` in the payload declares how many the
+List has, and `is_complete(held_indices)` answers whether the client has a
+fragment at every index below it. `merge` resolves a `frags` disagreement to the
+larger value. (`13302`, the single-event List, is retired by the spec — a
+replaceable kind cannot fragment.)
+
+The payload's 32-byte values are **unpadded base64url at every depth**, which is
+section-scoped to §8: CORD-05 invites stay hex. The writer re-encodes them on
+every serialization, so its output is always the canonical 43-character spelling;
+the reader also accepts non-zero trailing bits, because the spec's own worked
+example contains them and no reader can tell a mis-encoded named field from a
+correct one. The codec is `utils::base64url` and the wire structs behind the
+List's `Serialize`/`Deserialize` are the only callers, so no other encoding path
+is touched.
+
+Three write-time rules are folded into serialization, so an in-memory document
+and its wire form differ:
+
+- an embedded snapshot omits `community_id` and inherits the entry's;
+- `seed` is omitted when it equals `current`, and its cosmetic fields (`name`,
+  `relays`, each channel's `name`) are overwritten from `current` first, so a
+  rename collapses the snapshots instead of forking them;
+- an entry whose `added_at` does not outrun its tombstone is omitted — the
+  tombstone alone carries the state.
+
 `is_live(&id)` answers joined-versus-left: a tombstone is terminal until a
-strictly newer join outruns it. `fits()` is the write gate — 50 memberships and
-the NIP-44 size cap, both protocol constants.
+strictly newer join outruns it. `fits()` is the write gate: 50 memberships and
+the NIP-44 plaintext cap. The 50 is a stopgap inherited from the retired
+single-event design — §8 has **no membership limit**, its only bound is the
+65,536-byte encoded event, and the real fix is to start a new fragment on write
+(see `docs/concord-community-discovery-plan.md`, Phase D).
 
 ## GPUI integration
 
-`crates/concord` stays GPUI-free. The UI layer adds a registry global and one
+`crates/concord` stays GPUI-free; the registry and sync engine live in
+`crates/community`. That layer adds a registry global and one
 entity per community, and moves every decrypt, verification, fold and I/O off
 the foreground thread.
 
@@ -428,13 +467,13 @@ the foreground thread.
 Same shape as `ChatRegistry`:
 
 ```rust
-pub fn init(window: &mut Window, cx: &mut App) {
-    ConcordRegistry::set_global(cx.new(|cx| ConcordRegistry::new(window, cx)), cx);
+pub fn init(cx: &mut App) {
+    CommunityRegistry::set_global(cx.new(CommunityRegistry::new), cx);
 }
 
-impl ConcordRegistry {
+impl CommunityRegistry {
     pub fn global(cx: &App) -> Entity<Self> {
-        cx.global::<GlobalConcordRegistry>().0.clone()
+        cx.global::<GlobalCommunityRegistry>().0.clone()
     }
 }
 ```
@@ -443,8 +482,8 @@ Call it after `cord03::init` in `desktop/src/main.rs` and `web/src/lib.rs`, and
 subscribe to `NostrRegistry` for `SignerChanged` so the communities reset with
 the account.
 
-- `ConcordRegistry` holds `communities: Vec<Entity<Community>>`, an index by
-  `CommunityId`, and `tasks: SmallVec<[Task<Result<(), Error>>; 2]>`.
+- `CommunityRegistry` holds `communities: Vec<Entity<Community>>`, an index by
+  `CommunityId`, and `tasks: SmallVec<[Task<Result<()>>; 2]>`.
 - `Community` owns one `CommunityState`, the last `ControlFold`, the member list
   and the channel list. Views render `Entity<Community>`; no protocol state
   lives in a view.
@@ -459,7 +498,7 @@ A background task never touches an entity. It sends results through a bounded
 
 ```rust
 let (signal_tx, signal_rx) = flume::bounded::<Signal>(256);
-let database = client.database().clone();
+let client = client.clone();
 
 // Background: open, verify, fold — no entities.
 self.ingress = Some(cx.background_spawn(async move {
@@ -468,7 +507,7 @@ self.ingress = Some(cx.background_spawn(async move {
             continue;
         };
         let (opened, rumor) = cord03::open(wrap, &plane.group, &plane.channel, plane.epoch)?;
-        store::cache_rumor(database.as_ref(), &plane.channel, &opened).await?;
+        store::cache_rumor(&client, &plane.channel, &opened).await?;
         signal_tx.send_async(Signal::Chat { channel: plane.channel, rumor }).await?;
     }
     Ok(())
@@ -483,8 +522,8 @@ self.consumer = Some(cx.spawn(async move |this, cx| {
 }));
 ```
 
-- `client.database()` is a `&Arc<dyn NostrDatabase>` and `store::save_state`
-  wants `&dyn NostrDatabase`, so clone the `Arc` and pass `database.as_ref()`.
+- Every store function takes the `&Client` and reaches the database through
+  `client.database()`, so clone the `Client` into the background task.
 - Keep long-lived tasks in fields — dropping a `Task` cancels it. Assign `None`
   to an `Option<Task<_>>` before respawning it; a signer change replaces both
   the listener and the consumer.
@@ -493,8 +532,9 @@ self.consumer = Some(cx.spawn(async move |this, cx| {
 - Do the first load in `cx.defer_in(window, ...)` so `init` returns before the
   first relay request.
 - NIP-46 signing is async: call `signer.get_public_key_async()` /
-  `sign_event_async` inside the background task. The builders still take
-  `&Keys`, so run them where device keys are available.
+  `sign_event_async` inside the background task. Every account-key writer takes
+  any signer (`Keys` or the app's `UniversalSigner`) and is `async`, so `await`
+  it there rather than requiring device keys.
 
 ### Subscriptions
 
@@ -527,13 +567,30 @@ client.subscribe(filter).with_id(sub_id).await?;
 
 ## Not wired up yet
 
-- **No registry and no sync engine.** `crates/concord` has no subscriptions, no
-  `init`, and no `Entity<Community>`; the UI owns subscribing, routing a wrap to
-  the plane whose address it carries, and rebuilding a subscription when a plane's
-  address changes (join, channel added, rekey folded). GPUI integration above is
-  the shape to build, not code that exists.
-- **Every writer takes `&Keys`, not a `NostrSigner`.** NIP-46 is one deliberate
-  pass over the builders, not a per-call patch.
+- **`crates/concord` stays protocol-only; the registry lives in
+  `crates/community`.** `concord` has no subscriptions, no `init`, and no
+  `Entity<Community>`; `community::CommunityRegistry` owns one `Entity<Community>`
+  per state document, subscribes when a community's plane set changes, and
+  re-folds on an inbound wrap. The sidebar observes the registry, logs
+  `CommunityEvent::Error` through `log::error!`, and its "New community" row opens
+  a name prompt that calls `CommunityRegistry::create`. `create` still persists
+  the genesis locally without publishing it to the metadata's relays. Discovery
+  is local-only: `load` reads the state documents already in
+  `client.database()` and never fetches the account's CORD-02 Community List
+  (`33302`) from relays, so a fresh install — or one signing in as an account
+  that joined elsewhere — finds nothing and never subscribes. See
+  `docs/concord-community-discovery-plan.md`.
+- **Account-key writers take any signer, not `&Keys`.** `genesis`,
+  `ControlWriter`, the guestbook and chat `seal_rumor`s, the `list` builders, and
+  the `cord05` invite writers (`build_direct_invite` / `unwrap_direct_invite`,
+  `build_invite_list` / `parse_invite_list`) and `cord06` blob writers
+  (`build_blob` / `open_blob`) are `async` and generic over the SDK's
+  `AsyncGetPublicKey` / `AsyncSignEvent` / `AsyncNip44` traits, so a `Keys` and an
+  app `UniversalSigner` both work. The NIP-59 paths (`build_direct_invite`,
+  `unwrap_direct_invite`) stay `Sized` because the SDK's gift-wrap helpers are.
+  Group-key and locally-held-secret writers (`cord01` wrap functions,
+  `cord05::build_bundle_event`, `store`) still take the raw key material they
+  genuinely need.
 - **`crates/chat/src/lib.rs::handle_notifications` treats every kind 1059 event as
   a NIP-59 gift wrap for the current user.** Concord wraps are kind 1059 too, so
   that handler must route by subscription id before any concord subscription goes