feat(#2039): list matrix identities in get_agent_meta

hive-ag3nt/src/mcp.rs

@@ -58,6 +58,7 @@ pub enum SocketReply {
         status_set_at: Option<i64>,
         hive_name: Option<String>,
         swarm_name: Option<String>,
+        matrix_accounts: Vec<hive_sh4re::MatrixIdentity>,
     },
     /// `create_repo` result — the new repo's full name + clone URL.
     RepoCreated {
@@ -109,6 +110,7 @@ impl From<hive_sh4re::Response> for SocketReply {
                 status_set_at,
                 hive_name,
                 swarm_name,
+                matrix_accounts,
             } => Self::AgentMeta {
                 name,
                 running,
@@ -117,6 +119,7 @@ impl From<hive_sh4re::Response> for SocketReply {
                 status_set_at,
                 hive_name,
                 swarm_name,
+                matrix_accounts,
             },
             hive_sh4re::Response::RepoCreated {
                 full_name,
@@ -452,6 +455,7 @@ pub fn format_agent_meta(resp: Result<SocketReply, anyhow::Error>) -> String {
             status_set_at,
             hive_name,
             swarm_name,
+            matrix_accounts,
         }) => {
             let rev = hyperhive_rev.as_deref().unwrap_or("<unknown>");
             let run = if running { "yes" } else { "no" };
@@ -498,6 +502,22 @@ pub fn format_agent_meta(resp: Result<SocketReply, anyhow::Error>) -> String {
                     }
                 }
             }
+            // Matrix identities the agent can act as (the `account` arg on
+            // the matrix tools). Listed only when matrix is provisioned, so
+            // non-matrix agents don't see an empty line.
+            if !matrix_accounts.is_empty() {
+                use std::fmt::Write as _;
+                out.push_str("\nmatrix_accounts:");
+                for acct in &matrix_accounts {
+                    let uid = acct.user_id.as_deref().unwrap_or("?");
+                    let primary = if acct.is_primary { " [primary]" } else { "" };
+                    let _ = write!(
+                        out,
+                        "\n  {} ({uid}) on {}{primary}",
+                        acct.name, acct.homeserver
+                    );
+                }
+            }
             out
         }
         Ok(SocketReply::Err(m)) => format!("get_agent_meta failed: {m}"),

hive-c0re/src/socket_server.rs

@@ -417,9 +417,24 @@ async fn handle_get_agent_meta(
         status_set_at,
         hive_name,
         swarm_name,
+        matrix_accounts: read_agent_matrix_identities(target),
     }
 }
 
+/// Read the target agent's matrix identities from the daemon's
+/// `matrix-accounts.json` snapshot (under the agent's state dir).
+/// Best-effort: an absent / unparseable snapshot (no matrix provisioning,
+/// or the daemon not up yet) yields an empty list. The `MatrixIdentity`
+/// serde shape matches the snapshot entries; the snapshot's `live` field is
+/// ignored (only live accounts are written).
+fn read_agent_matrix_identities(agent: &str) -> Vec<hive_sh4re::MatrixIdentity> {
+    let path = Coordinator::agent_notes_dir(agent).join("matrix-accounts.json");
+    std::fs::read_to_string(&path)
+        .ok()
+        .and_then(|s| serde_json::from_str::<Vec<hive_sh4re::MatrixIdentity>>(&s).ok())
+        .unwrap_or_default()
+}
+
 /// `Status` — count of pending (unread) inbox messages for `agent`.
 fn handle_status(coord: &Arc<Coordinator>, agent: &str) -> hive_sh4re::Response {
     match coord.broker.count_pending(agent) {

hive-sh4re/src/lib.rs

@@ -845,6 +845,10 @@ pub enum Response {
         hive_name: Option<String>,
         #[serde(default, skip_serializing_if = "Option::is_none")]
         swarm_name: Option<String>,
+        /// Matrix identities this agent can act as (one per configured +
+        /// live account). Empty for agents with no matrix provisioning.
+        #[serde(default, skip_serializing_if = "Vec::is_empty")]
+        matrix_accounts: Vec<MatrixIdentity>,
     },
     /// `GetLogs` result: journal lines for the requested container.
     /// Returned on the manager socket only.
@@ -918,6 +922,26 @@ pub struct AgentStatusRow {
     pub parent: Option<String>,
 }
 
+/// One matrix identity an agent can act as, surfaced in `GetAgentMeta`'s
+/// `matrix_accounts`. Field names match the daemon's `matrix-accounts.json`
+/// snapshot (written by `hive-matrix-mcp`'s account registry) so hive-c0re
+/// deserializes the snapshot straight into `Vec<MatrixIdentity>`; the
+/// snapshot's `live` field is ignored here (only live accounts are listed).
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct MatrixIdentity {
+    /// Logical account name (the `account` arg on the matrix MCP tools).
+    pub name: String,
+    /// Matrix user id (`@user:server`). `None` if the session restored
+    /// without a known user id yet.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub user_id: Option<String>,
+    /// Homeserver base URL this account is on.
+    pub homeserver: String,
+    /// Whether this is the primary account (selected when a matrix tool
+    /// call omits `account`).
+    pub is_primary: bool,
+}
+
 /// Serde default for the `running` field; keeps wire backwards-compat
 /// with pre-running-field payloads. See
 /// `docs/conventions.md::Agent metadata`.