feat: hint to do other work when recv/bash_status waits time out

When an agent parks on a long-poll that expires with nothing to show,
nudge it to spend the idle time on other useful work instead of
immediately re-blocking on the same call.

- recv: when wait_seconds > 0 and the inbox is empty at timeout, the
  '(empty)' result now carries IDLE_WAIT_HINT. Immediate peeks
  (no/zero wait) are unchanged.
- bash_status: when wait_seconds > 0 and the task is still
  pending/running at timeout, append BASH_IDLE_WAIT_HINT. Finished
  tasks and no-wait calls are unchanged.

Both thread a 'waited' flag into the formatter so the hint only fires
on an actual wait-timeout. Unit tests cover both. Implements #1411.

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

@@ -119,11 +119,27 @@ fn render_bash_run(id: &str, resp: Result<DaemonResponse>) -> String {
     }
 }
 
+/// Appended to a `status` result when the caller parked on a
+/// `wait_seconds` poll that expired while the task was still running —
+/// nudges the model to spend the idle time on other work instead of
+/// immediately re-waiting on the same task.
+const BASH_IDLE_WAIT_HINT: &str = "\n\nThe task is still running — your wait timed out before it \
+finished. If you have other useful work, do that and check back later (the task keeps running, and \
+a wake fires when it completes) rather than immediately re-waiting.";
+
 /// Turn a `DaemonResponse` from a `BashStatus` call into the string
-/// claude sees as the tool result.
-fn render_bash_status(id: &str, resp: Result<DaemonResponse>) -> String {
+/// claude sees as the tool result. When `waited` is set (the call
+/// parked on a `wait_seconds` poll) and the task is still non-terminal,
+/// [`BASH_IDLE_WAIT_HINT`] is appended.
+fn render_bash_status(id: &str, resp: Result<DaemonResponse>, waited: bool) -> String {
     match resp {
-        Ok(DaemonResponse::Ok { payload }) => format_task(id, &payload),
+        Ok(DaemonResponse::Ok { payload }) => {
+            let mut out = format_task(id, &payload);
+            if waited && matches!(payload["status"].as_str(), Some("pending" | "running")) {
+                out.push_str(BASH_IDLE_WAIT_HINT);
+            }
+            out
+        }
         Ok(DaemonResponse::Error { message }) => message,
         Err(e) => format!("bash bridge error: {e:#}"),
     }
@@ -215,11 +231,12 @@ impl BashMcp {
     )]
     async fn status(&self, Parameters(args): Parameters<BashStatusArgs>) -> String {
         let id = args.id.clone();
+        let waited = args.wait_seconds.is_some_and(|w| w > 0);
         let req = DaemonRequest::BashStatus {
             id: args.id,
             wait_seconds: args.wait_seconds,
         };
-        render_bash_status(&id, round_trip(req).await)
+        render_bash_status(&id, round_trip(req).await, waited)
     }
 }
 
@@ -240,3 +257,34 @@ async fn main() -> Result<()> {
     service.waiting().await?;
     Ok(())
 }
+
+#[cfg(test)]
+mod status_hint_tests {
+    use super::{BASH_IDLE_WAIT_HINT, render_bash_status};
+    use anyhow::Result;
+    use hive_bash_mcp::protocol::DaemonResponse;
+
+    fn ok(status: &str) -> Result<DaemonResponse> {
+        Ok(DaemonResponse::Ok {
+            payload: serde_json::json!({ "status": status, "started_at": 1 }),
+        })
+    }
+
+    #[test]
+    fn running_task_after_wait_appends_idle_hint() {
+        let out = render_bash_status("t1", ok("running"), true);
+        assert!(out.contains(BASH_IDLE_WAIT_HINT));
+    }
+
+    #[test]
+    fn running_task_without_wait_has_no_hint() {
+        let out = render_bash_status("t1", ok("running"), false);
+        assert!(!out.contains(BASH_IDLE_WAIT_HINT));
+    }
+
+    #[test]
+    fn finished_task_after_wait_has_no_hint() {
+        let out = render_bash_status("t1", ok("done"), true);
+        assert!(!out.contains(BASH_IDLE_WAIT_HINT));
+    }
+}