Skip unchanged live-sync streams

AGENTS.md

@@ -109,7 +109,9 @@ Roadmap items should be actionable and checkable:
   and `geth peer auth-check` over Iroh, signed peer-card LAN discovery payloads,
   authorized `geth cas fetch`, `geth ssh cert sync`, and
   `geth ssh revocation sync` over the Iroh control ALPN, a background SSH
-  metadata and KV live-sync loop with per-peer cursors in `module_state`,
+  metadata and KV live-sync loop with per-peer cursors in `module_state` and an
+  authorized sync-status summary that lets peers disclose only permitted stream
+  watermarks before module pulls,
   untrusted discovery-backend trait, custom relay-map config, and Iroh
   local-network discovery toggle exist.
 - Canonical signed-operation envelopes exist for keychain/auth signature

README.md

@@ -146,6 +146,10 @@ approval/signing workflows. While the daemon is running, it also performs a
 background live-sync tick for known peers every 30 seconds. Live-sync stores
 per-peer high-water cursors in local metadata so repeated ticks request only
 newer SSH certificate-flow and revocation records.
+Before probing individual modules, the daemon asks the peer for an authorized
+sync-status summary over Iroh. The peer only returns stream watermarks for
+resources where the caller already has the matching capability, letting the
+local daemon skip unchanged or unauthorized streams.
 Named KV stores participate in the same live-sync loop once they exist locally:
 manual `geth kv sync <node-id> <name>` and background ticks require `kv.read`
 on the remote `resource:kv:<name>` and import only remote entries that are not

crates/geth-control/src/lib.rs

@@ -571,6 +571,10 @@ pub enum PeerControlRequest {
         capability: String,
         nonce: String,
     },
+    SyncStatus {
+        peer_card: PeerCard,
+        nonce: String,
+    },
     CasFetch {
         peer_card: PeerCard,
         hash: BlobHash,
@@ -643,6 +647,15 @@ pub enum PeerControlResponse {
         nonce: String,
         note: String,
     },
+    SyncStatus {
+        node_id: String,
+        agent_id: String,
+        endpoint_id: String,
+        remote_endpoint_id: String,
+        watermarks: Vec<SyncWatermark>,
+        nonce: String,
+        note: String,
+    },
     CasFetched {
         node_id: String,
         agent_id: String,
@@ -755,6 +768,12 @@ pub enum PeerControlResponse {
     },
 }
 
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct SyncWatermark {
+    pub stream: String,
+    pub high_water: i64,
+}
+
 #[derive(Debug, thiserror::Error)]
 pub enum ControlError {
     #[error("json error: {0}")]
@@ -1118,6 +1137,24 @@ mod tests {
             response
         );
 
+        let response = PeerControlResponse::SyncStatus {
+            node_id: "node:peer".to_owned(),
+            agent_id: "agent:peer".to_owned(),
+            endpoint_id: "endpoint:peer".to_owned(),
+            remote_endpoint_id: "endpoint:caller".to_owned(),
+            watermarks: vec![SyncWatermark {
+                stream: "kv:prefs".to_owned(),
+                high_water: 42,
+            }],
+            nonce: "nonce".to_owned(),
+            note: "status".to_owned(),
+        };
+        assert_eq!(
+            decode_peer_response(&encode_peer_response(&response).expect("encode"))
+                .expect("decode"),
+            response
+        );
+
         let response = PeerControlResponse::CasFetched {
             node_id: "node:peer".to_owned(),
             agent_id: "agent:peer".to_owned(),
@@ -1161,6 +1198,26 @@ mod tests {
             request
         );
 
+        let request = PeerControlRequest::SyncStatus {
+            peer_card: PeerCard {
+                node_id: "node:caller".into(),
+                agent_id: "agent:caller".into(),
+                endpoints: Vec::new(),
+                issued_at: geth_types::UnixMillis(1),
+                signature: geth_discovery::SignatureMetadata {
+                    namespace: "geth.peer-card.v1@geth.local".to_owned(),
+                    signer: "agent:caller".to_owned(),
+                    public_key: "key".to_owned(),
+                    signature: "sig".to_owned(),
+                },
+            },
+            nonce: "nonce".to_owned(),
+        };
+        assert_eq!(
+            decode_peer_request(&encode_peer_request(&request).expect("encode")).expect("decode"),
+            request
+        );
+
         let response = PeerControlResponse::SshCertSynced {
             node_id: "node:peer".to_owned(),
             agent_id: "agent:peer".to_owned(),

crates/geth-node/src/lib.rs

@@ -9,7 +9,7 @@ use geth_cas::{
 use geth_config::{GethConfig, GethPaths, RelayMode};
 use geth_control::{
     CasBlob, ControlRequest, ControlResponse, KeychainStatusResponse, NodeIdResponse,
-    PeerControlRequest, PeerControlResponse, StatusResponse,
+    PeerControlRequest, PeerControlResponse, StatusResponse, SyncWatermark,
 };
 use geth_crypto::AgentKey;
 use geth_db::DbResource;
@@ -554,7 +554,8 @@ async fn peer_ping(node: &LocalNode, peer_node: &str) -> Result<ControlResponse,
         PeerControlResponse::AuthChecked { .. } => Err(NodeError::IrohPeer(
             "peer returned auth-check response to ping request".to_owned(),
         )),
-        PeerControlResponse::CasFetched { .. }
+        PeerControlResponse::SyncStatus { .. }
+        | PeerControlResponse::CasFetched { .. }
         | PeerControlResponse::SshCertSynced { .. }
         | PeerControlResponse::SshRevocationSynced { .. }
         | PeerControlResponse::KvSynced { .. }
@@ -666,7 +667,8 @@ async fn peer_auth_check(
         PeerControlResponse::Pong { .. } => Err(NodeError::IrohPeer(
             "peer returned pong to auth-check request".to_owned(),
         )),
-        PeerControlResponse::CasFetched { .. }
+        PeerControlResponse::SyncStatus { .. }
+        | PeerControlResponse::CasFetched { .. }
         | PeerControlResponse::SshCertSynced { .. }
         | PeerControlResponse::SshRevocationSynced { .. }
         | PeerControlResponse::KvSynced { .. }
@@ -808,6 +810,7 @@ async fn cas_fetch_from_peer(
         PeerControlResponse::Error { message } => Err(NodeError::IrohPeer(message)),
         PeerControlResponse::Pong { .. }
         | PeerControlResponse::AuthChecked { .. }
+        | PeerControlResponse::SyncStatus { .. }
         | PeerControlResponse::SshCertSynced { .. }
         | PeerControlResponse::SshRevocationSynced { .. }
         | PeerControlResponse::KvSynced { .. }
@@ -1220,6 +1223,28 @@ async fn document_sync_from_peer(
     }
 }
 
+async fn sync_status_from_peer(
+    node: &LocalNode,
+    peer_node: &str,
+) -> Result<Vec<SyncWatermark>, NodeError> {
+    let response = request_peer_control(node, peer_node, "sync-status", |peer_card, nonce| {
+        PeerControlRequest::SyncStatus { peer_card, nonce }
+    })
+    .await?;
+    match response {
+        PeerControlResponse::SyncStatus {
+            watermarks, note, ..
+        } => {
+            tracing::debug!(peer = %peer_node, %note, streams = watermarks.len(), "peer sync status received");
+            Ok(watermarks)
+        }
+        PeerControlResponse::Error { message } => Err(NodeError::IrohPeer(message)),
+        _ => Err(NodeError::IrohPeer(
+            "peer returned wrong response type to sync status".to_owned(),
+        )),
+    }
+}
+
 async fn db_sync_from_peer(
     node: &LocalNode,
     peer_node: &str,
@@ -1335,6 +1360,121 @@ fn store_live_sync_cursor(
     Ok(())
 }
 
+fn should_live_sync_stream(
+    store: &Store,
+    peer_node: &str,
+    stream: &str,
+    remote_watermarks: Option<&BTreeMap<String, i64>>,
+) -> Result<bool, NodeError> {
+    let Some(remote_watermarks) = remote_watermarks else {
+        return Ok(true);
+    };
+    let Some(remote_high_water) = remote_watermarks.get(stream) else {
+        return Ok(false);
+    };
+    if *remote_high_water == 0 {
+        return Ok(false);
+    }
+    let local_cursor = load_live_sync_cursor(store, peer_node, stream)?;
+    if stream.starts_with("db:") {
+        Ok(*remote_high_water > local_cursor)
+    } else {
+        Ok(*remote_high_water >= local_cursor)
+    }
+}
+
+fn sync_watermarks_for_peer(
+    store: &Store,
+    peer_node: &str,
+) -> Result<Vec<SyncWatermark>, NodeError> {
+    let mut watermarks = Vec::new();
+    let peer = PrincipalId::new(peer_node.to_owned());
+    if can_sync_resource(store, &peer, "resource:ssh:certs", "ssh_cert.sync")? {
+        let cert_high = store
+            .list_ssh_cert_requests()?
+            .into_iter()
+            .map(|request| request.created_at_ms)
+            .chain(
+                store
+                    .list_ssh_certificates()?
+                    .into_iter()
+                    .map(|certificate| certificate.imported_at_ms),
+            )
+            .max()
+            .unwrap_or(0);
+        watermarks.push(SyncWatermark {
+            stream: "ssh-certs".to_owned(),
+            high_water: cert_high,
+        });
+    }
+    if can_sync_resource(
+        store,
+        &peer,
+        "resource:ssh:revocations",
+        "ssh_revocation.sync",
+    )? {
+        let revocation_high = store
+            .list_ssh_revocations()?
+            .into_iter()
+            .map(|revocation| revocation.created_at_ms)
+            .max()
+            .unwrap_or(0);
+        watermarks.push(SyncWatermark {
+            stream: "ssh-revocations".to_owned(),
+            high_water: revocation_high,
+        });
+    }
+    for kv in store.list_kv_stores()? {
+        if can_sync_resource(store, &peer, &kv.resource_id, "kv.read")? {
+            let high_water = store
+                .list_kv_entries_since(&kv.kv_id, 0)?
+                .into_iter()
+                .map(|entry| entry.updated_at_ms)
+                .max()
+                .unwrap_or(0);
+            watermarks.push(SyncWatermark {
+                stream: format!("kv:{}", kv.name),
+                high_water,
+            });
+        }
+    }
+    for document in store.list_document_resources()? {
+        if can_sync_resource(store, &peer, &document.resource_id, "document.read")? {
+            watermarks.push(SyncWatermark {
+                stream: format!("document:{}", document.name),
+                high_water: document.updated_at_ms,
+            });
+        }
+    }
+    for db in store.list_db_resources()? {
+        if can_sync_resource(store, &peer, &db.resource_id, "db.sync")? {
+            if let Ok(metadata) = geth_db::crsqlite_change_metadata(Path::new(&db.path)) {
+                watermarks.push(SyncWatermark {
+                    stream: format!("db:{}", db.name),
+                    high_water: metadata.max_db_version.unwrap_or(0),
+                });
+            }
+        }
+    }
+    watermarks.sort_by(|left, right| left.stream.cmp(&right.stream));
+    Ok(watermarks)
+}
+
+fn can_sync_resource(
+    store: &Store,
+    peer: &PrincipalId,
+    resource: &str,
+    capability: &str,
+) -> Result<bool, NodeError> {
+    Ok(geth_auth::explain_auth_ops(
+        &load_auth_ops_for_resource(store, resource)?,
+        peer.clone(),
+        ResourceId::new(resource.to_owned()),
+        Capability::new(capability.to_owned()),
+    )
+    .allowed)
+}
+
 async fn request_peer_control(
     node: &LocalNode,
     peer_node: &str,
@@ -1420,6 +1560,10 @@ async fn request_peer_control(
         | PeerControlResponse::DbSynced {
             nonce: response_nonce,
             ..
+        }
+        | PeerControlResponse::SyncStatus {
+            nonce: response_nonce,
+            ..
         } if response_nonce == &nonce => Ok(response),
         PeerControlResponse::Error { .. } => Ok(response),
         _ => Err(NodeError::IrohPeer(format!(
@@ -1471,25 +1615,68 @@ async fn run_live_sync_once(node: &LocalNode) -> Result<(), NodeError> {
     let documents = Store::open(&node.paths.metadata_db())?.list_document_resources()?;
     let dbs = Store::open(&node.paths.metadata_db())?.list_db_resources()?;
     for peer in peers {
-        if let Err(error) = ssh_cert_sync_from_peer(node, &peer.peer_id).await {
-            tracing::debug!(peer = %peer.peer_id, %error, "SSH cert live sync failed");
+        let store = Store::open(&node.paths.metadata_db())?;
+        let remote_watermarks = match sync_status_from_peer(node, &peer.peer_id).await.map(
+            |watermarks| {
+                watermarks
+                    .into_iter()
+                    .map(|watermark| (watermark.stream, watermark.high_water))
+                    .collect::<BTreeMap<_, _>>()
+            },
+        ) {
+            Ok(watermarks) => Some(watermarks),
+            Err(error) => {
+                tracing::debug!(peer = %peer.peer_id, %error, "sync status failed; falling back to direct live-sync probes");
+                None
+            }
+        };
+        if should_live_sync_stream(
+            &store,
+            &peer.peer_id,
+            "ssh-certs",
+            remote_watermarks.as_ref(),
+        )? {
+            if let Err(error) = ssh_cert_sync_from_peer(node, &peer.peer_id).await {
+                tracing::debug!(peer = %peer.peer_id, %error, "SSH cert live sync failed");
+            }
         }
-        if let Err(error) = ssh_revocation_sync_from_peer(node, &peer.peer_id).await {
-            tracing::debug!(peer = %peer.peer_id, %error, "SSH revocation live sync failed");
+        if should_live_sync_stream(
+            &store,
+            &peer.peer_id,
+            "ssh-revocations",
+            remote_watermarks.as_ref(),
+        )? {
+            if let Err(error) = ssh_revocation_sync_from_peer(node, &peer.peer_id).await {
+                tracing::debug!(peer = %peer.peer_id, %error, "SSH revocation live sync failed");
+            }
         }
         for kv in &kv_stores {
-            if let Err(error) = kv_sync_from_peer(node, &peer.peer_id, &kv.name).await {
-                tracing::debug!(peer = %peer.peer_id, kv = %kv.name, %error, "KV live sync failed");
+            let stream = format!("kv:{}", kv.name);
+            if should_live_sync_stream(&store, &peer.peer_id, &stream, remote_watermarks.as_ref())?
+            {
+                if let Err(error) = kv_sync_from_peer(node, &peer.peer_id, &kv.name).await {
+                    tracing::debug!(peer = %peer.peer_id, kv = %kv.name, %error, "KV live sync failed");
+                }
             }
         }
         for document in &documents {
-            if let Err(error) = document_sync_from_peer(node, &peer.peer_id, &document.name).await {
-                tracing::debug!(peer = %peer.peer_id, document = %document.name, %error, "document live sync failed");
+            let stream = format!("document:{}", document.name);
+            if should_live_sync_stream(&store, &peer.peer_id, &stream, remote_watermarks.as_ref())?
+            {
+                if let Err(error) =
+                    document_sync_from_peer(node, &peer.peer_id, &document.name).await
+                {
+                    tracing::debug!(peer = %peer.peer_id, document = %document.name, %error, "document live sync failed");
+                }
             }
         }
         for db in &dbs {
-            if let Err(error) = db_sync_from_peer(node, &peer.peer_id, &db.name, 100).await {
-                tracing::debug!(peer = %peer.peer_id, db = %db.name, %error, "DB live sync failed");
+            let stream = format!("db:{}", db.name);
+            if should_live_sync_stream(&store, &peer.peer_id, &stream, remote_watermarks.as_ref())?
+            {
+                if let Err(error) = db_sync_from_peer(node, &peer.peer_id, &db.name, 100).await {
+                    tracing::debug!(peer = %peer.peer_id, db = %db.name, %error, "DB live sync failed");
+                }
             }
         }
     }
@@ -1546,6 +1733,31 @@ async fn handle_iroh_control_connection(
                 note: "peer endpoint authenticated by Iroh and peer-card signature; candidate status does not grant resource capabilities".to_owned(),
             }
         }
+        PeerControlRequest::SyncStatus { peer_card, nonce } => {
+            peer_card.validate_candidate()?;
+            ensure_peer_card_matches_endpoint(&peer_card, &remote_endpoint_id)?;
+            let discovered = DiscoveredPeer::candidate(
+                peer_card.clone(),
+                UnixMillis(geth_store::now_ms()),
+                DiscoverySource::PeerExchange,
+            )?;
+            let store = Store::open(&node.paths.metadata_db())?;
+            store.upsert_peer_card(&StoredPeerCard {
+                peer_id: peer_card.node_id.to_string(),
+                card_json: serde_json::to_string(&peer_card)?,
+                updated_at_ms: discovered.discovered_at.0,
+            })?;
+            let watermarks = sync_watermarks_for_peer(&store, peer_card.node_id.as_str())?;
+            PeerControlResponse::SyncStatus {
+                node_id: node.node_id.clone(),
+                agent_id: node.agent_id.clone(),
+                endpoint_id: node.iroh_status.endpoint_id.clone().unwrap_or_default(),
+                remote_endpoint_id,
+                watermarks,
+                nonce,
+                note: "sync status authenticated endpoint/card binding and returns only streams for capabilities already granted to the caller".to_owned(),
+            }
+        }
         PeerControlRequest::AuthCheck {
             peer_card,
             resource,
@@ -3707,6 +3919,114 @@ mod tests {
         .expect("insert mock crsqlite change");
     }
 
+    fn grant_test_capability(store: &Store, peer: &str, resource: &str, capability: &str) {
+        let created_at = UnixMillis(geth_store::now_ms());
+        store_auth_op(
+            store,
+            &AuthOp {
+                id: generated_auth_op_id("grant-create", resource, capability, created_at),
+                resource: ResourceId::new(resource.to_owned()),
+                created_at,
+                kind: AuthOpKind::GrantCreate {
+                    grant_id: format!("grant:{peer}:{resource}:{capability}"),
+                    principal: PrincipalId::new(peer.to_owned()),
+                    capabilities: vec![Capability::new(capability.to_owned())],
+                },
+            },
+        )
+        .expect("store auth grant");
+    }
+
+    #[test]
+    fn sync_watermarks_include_only_authorized_streams() {
+        let store = Store::open_memory().expect("open");
+        store
+            .insert_resource(&StoredResource {
+                resource_id: "resource:kv:prefs".to_owned(),
+                kind: "kv".to_owned(),
+                name: "prefs".to_owned(),
+                status: "active".to_owned(),
+            })
+            .expect("insert kv resource");
+        store
+            .insert_kv_store(&StoredKvStore {
+                kv_id: "kv:prefs".to_owned(),
+                resource_id: "resource:kv:prefs".to_owned(),
+                name: "prefs".to_owned(),
+            })
+            .expect("insert kv");
+        store
+            .set_kv_entry(&StoredKvEntry {
+                kv_id: "kv:prefs".to_owned(),
+                key: "theme".to_owned(),
+                value: "dark".to_owned(),
+                updated_at_ms: 42,
+            })
+            .expect("set kv");
+
+        store
+            .insert_resource(&StoredResource {
+                resource_id: "resource:document:notes".to_owned(),
+                kind: "document".to_owned(),
+                name: "notes".to_owned(),
+                status: "active".to_owned(),
+            })
+            .expect("insert document resource");
+        store
+            .insert_document_resource(&StoredDocumentResource {
+                document_id: "document:notes".to_owned(),
+                resource_id: "resource:document:notes".to_owned(),
+                name: "notes".to_owned(),
+                state_json: "{}".to_owned(),
+                updated_at_ms: 99,
+            })
+            .expect("insert document");
+
+        let dir = tempfile::tempdir().expect("tempdir");
+        let db_path = dir.path().join("notes.sqlite");
+        create_mock_crsqlite_db(&db_path, Some(7));
+        store
+            .insert_resource(&StoredResource {
+                resource_id: "resource:db:notes".to_owned(),
+                kind: "db".to_owned(),
+                name: "notes".to_owned(),
+                status: "active".to_owned(),
+            })
+            .expect("insert db resource");
+        store
+            .insert_db_resource(&StoredDbResource {
+                db_id: "db:notes".to_owned(),
+                resource_id: "resource:db:notes".to_owned(),
+                name: "notes".to_owned(),
+                path: db_path.display().to_string(),
+            })
+            .expect("insert db");
+
+        grant_test_capability(&store, "node:left", "resource:kv:prefs", "kv.read");
+        grant_test_capability(&store, "node:left", "resource:db:notes", "db.sync");
+
+        let watermarks = sync_watermarks_for_peer(&store, "node:left").expect("watermarks");
+
+        assert!(watermarks.contains(&SyncWatermark {
+            stream: "kv:prefs".to_owned(),
+            high_water: 42,
+        }));
+        assert!(watermarks.contains(&SyncWatermark {
+            stream: "db:notes".to_owned(),
+            high_water: 7,
+        }));
+        assert!(
+            !watermarks
+                .iter()
+                .any(|watermark| watermark.stream == "document:notes")
+        );
+        assert!(
+            !watermarks
+                .iter()
+                .any(|watermark| watermark.stream == "ssh-certs")
+        );
+    }
+
     #[test]
     fn lan_discovery_address_selection_uses_iroh_direct_addresses() {
         let key = AgentKey::generate();

docs/architecture.md

@@ -89,6 +89,11 @@ live-sync tick for known peers and records per-peer high-water cursors in
 `module_state`, so repeated ticks request only records at or beyond the last
 remote cursor. Boundary duplicates are harmless because records are keyed by
 stable IDs and inserted with replace semantics.
+Before issuing per-module pulls, the daemon can request an authorized sync
+status summary over the same protected Iroh control ALPN. The serving peer
+validates endpoint/card binding and returns only watermarks for streams where
+the caller already has the required resource capability, which reduces blind
+polling without letting discovery reveal private resource names.
 
 ## Resource Model
 
@@ -197,7 +202,8 @@ unsupported and asks for JSONL or the spec source. Revocation lists are not yet
 full CRDT-replicated resources, but the daemon can already pull cert-flow and
 revocation metadata from authorized peers over the protected Iroh control ALPN.
 Manual sync commands and the background live-sync loop share the same capability
-checks and cursor state.
+checks and cursor state. The live-sync loop first asks for authorized stream
+watermarks and skips module pulls whose remote high-water value has not advanced.
 
 ## Keychain, Auth, And Secrets
 

docs/roadmap.md

@@ -140,6 +140,18 @@ geth-to-geth connections without granting trust from discovery alone.
   - `[x]` Protected module handlers reject requests that only know an
     EndpointID and lack resource capabilities.
 
+- `[x]` Authorized sync status summary.
+  Acceptance criteria:
+  - `[x]` The daemon can ask an imported peer for sync stream watermarks over
+    the protected Iroh control ALPN.
+  - `[x]` The serving peer validates the caller's signed peer card against the
+    observed Iroh EndpointID before returning watermarks.
+  - `[x]` The serving peer only includes streams where the caller already has
+    the relevant resource capability.
+  - `[x]` Background live-sync skips per-module pulls when the authorized remote
+    watermark has not advanced.
+  - `[x]` Tests verify unauthorized streams are omitted from summary output.
+
 ## Phase 2: Trust And Authorization
 
 Goal: replace stubs with signed, reducible keychain/auth operation logs and