fix(#2033): gate matrix mcp bridge startup on token, not daemon socket

hive-matrix-mcp/src/bin/mcp.rs

@@ -576,16 +576,28 @@ async fn main() -> Result<()> {
         .with_writer(std::io::stderr)
         .init();
 
-    // Standalone-degraded boot: missing daemon socket → exit 0
-    // cleanly so claude doesn't see an MCP startup error when matrix
-    // hasn't been provisioned for this agent yet. The daemon will
-    // appear once hive-c0re writes the token + systemd starts the
-    // daemon unit.
-    let socket = paths::daemon_socket();
-    if !tokio::fs::try_exists(&socket).await.unwrap_or(false) {
+    // Standalone-degraded boot: matrix isn't provisioned for this agent
+    // (no token file) → exit 0 cleanly so claude doesn't register a
+    // matrix MCP server it can never use.
+    //
+    // Gate on the TOKEN, not the daemon socket. The daemon binds its
+    // socket only AFTER restoring its matrix session (~10s on a cold
+    // boot), so an exists-check on the socket here raced the daemon's
+    // startup: during that window the socket was absent, the bridge
+    // exited, and claude lost the matrix tools for the WHOLE session
+    // (the bridge isn't respawned mid-turn). The token, by contrast, is
+    // written by hive-c0re at provisioning time and is present well
+    // before the daemon finishes booting — so it cleanly distinguishes
+    // "matrix not set up for this agent" (token absent → exit) from
+    // "daemon still coming up" (token present → keep serving). When the
+    // token exists we serve regardless of socket state: tool calls
+    // `connect()` per-call and simply error until the daemon is up, but
+    // the tools stay registered for the session. (#2033)
+    let token_file = paths::token_file();
+    if !tokio::fs::try_exists(&token_file).await.unwrap_or(false) {
         tracing::warn!(
-            path = %socket.display(),
-            "matrix daemon socket absent; exiting cleanly so MCP startup doesn't fail"
+            path = %token_file.display(),
+            "matrix not provisioned (no token file); exiting cleanly so MCP startup doesn't fail"
         );
         return Ok(());
     }