feat(jobs): exempt polling tools from loop tracker and hint on unchanged checks

src/function/jobs.rs

@@ -479,6 +479,7 @@ async fn handle_start(ctx: &mut RequestContext, args: &Value) -> Result<Value> {
         state,
         output_buf,
         no_change_checks: 0,
+        last_check_state: None,
     };
 
     // On a capacity race the handle is dropped here, which kills the process
@@ -507,8 +508,8 @@ fn handle_check(ctx: &RequestContext, args: &Value) -> Result<Value> {
     let Some(supervisor) = ctx.supervisor.as_ref() else {
         return Ok(job_miss_error(None, id));
     };
-    let sup = supervisor.read();
+    let mut sup = supervisor.write();
-    let Some(job) = sup.job(id) else {
+    let Some(job) = sup.job_mut(id) else {
         drop(sup);
         return Ok(job_miss_error(ctx.supervisor.as_ref(), id));
     };
@@ -518,6 +519,13 @@ fn handle_check(ctx: &RequestContext, args: &Value) -> Result<Value> {
         let buf = job.output_buf.lock();
         (buf.tail(), buf.total_written())
     };
+    let check_state = (status, total_written);
+    if job.last_check_state == Some(check_state) {
+        job.no_change_checks += 1;
+    } else {
+        job.no_change_checks = 0;
+        job.last_check_state = Some(check_state);
+    }
     let tail_truncated = (tail.len() as u64) < total_written;
     let mut result = json!({
         "status": job_status_str(status),
@@ -532,6 +540,11 @@ fn handle_check(ctx: &RequestContext, args: &Value) -> Result<Value> {
         result["message"] = json!(
             "Job is still running. Call job__collect to block for the result, or do other work — you will be notified on completion."
         );
+        if job.no_change_checks >= 3 {
+            result["hint"] = json!(
+                "No change across repeated checks — still running; call job__collect to block, or do other work — a system notification will fire on completion."
+            );
+        }
     } else {
         result["message"] = json!(format!(
             "Job finished — retrieve the result with job__collect --id {id}"
@@ -1175,6 +1188,7 @@ mod tests {
             })),
             output_buf: Arc::new(Mutex::new(RingBuf::default())),
             no_change_checks: 0,
+            last_check_state: None,
         }
     }
 
@@ -1640,6 +1654,7 @@ mod tests {
                 })),
                 output_buf: Arc::new(Mutex::new(RingBuf::default())),
                 no_change_checks: 0,
+                last_check_state: None,
             };
             ctx.supervisor
                 .as_ref()
@@ -1754,6 +1769,86 @@ mod tests {
         assert!(ctx.supervisor.as_ref().unwrap().read().has_job("j1"));
     }
 
+    #[test]
+    fn handle_check_hints_after_repeated_unchanged_checks() {
+        let ctx = ctx_with_job_supervisor(4);
+        ctx.supervisor
+            .as_ref()
+            .unwrap()
+            .write()
+            .register(make_running_job("j1"))
+            .unwrap();
+
+        for _ in 0..3 {
+            let result = handle_check(&ctx, &json!({"id": "j1"})).unwrap();
+            assert!(result.get("hint").is_none());
+        }
+        let result = handle_check(&ctx, &json!({"id": "j1"})).unwrap();
+        assert_eq!(
+            result["hint"],
+            "No change across repeated checks — still running; call job__collect to block, or do other work — a system notification will fire on completion."
+        );
+    }
+
+    #[test]
+    fn handle_check_no_change_counter_resets_on_output_change() {
+        let ctx = ctx_with_job_supervisor(4);
+        let job = make_running_job("j1");
+        let output_buf = Arc::clone(&job.output_buf);
+        ctx.supervisor
+            .as_ref()
+            .unwrap()
+            .write()
+            .register(job)
+            .unwrap();
+
+        for _ in 0..3 {
+            handle_check(&ctx, &json!({"id": "j1"})).unwrap();
+        }
+        assert!(
+            handle_check(&ctx, &json!({"id": "j1"}))
+                .unwrap()
+                .get("hint")
+                .is_some()
+        );
+
+        output_buf.lock().push(b"more");
+        for _ in 0..3 {
+            let result = handle_check(&ctx, &json!({"id": "j1"})).unwrap();
+            assert!(result.get("hint").is_none());
+        }
+        assert!(
+            handle_check(&ctx, &json!({"id": "j1"}))
+                .unwrap()
+                .get("hint")
+                .is_some()
+        );
+    }
+
+    #[test]
+    fn handle_check_finished_job_never_hints() {
+        let ctx = ctx_with_job_supervisor(4);
+        let job = make_running_job("j1");
+        job.state.lock().status = JobStatus::Completed;
+        ctx.supervisor
+            .as_ref()
+            .unwrap()
+            .write()
+            .register(job)
+            .unwrap();
+
+        for _ in 0..5 {
+            let result = handle_check(&ctx, &json!({"id": "j1"})).unwrap();
+            assert!(result.get("hint").is_none());
+            assert!(
+                result["message"]
+                    .as_str()
+                    .unwrap()
+                    .contains("job__collect --id j1")
+            );
+        }
+    }
+
     #[test]
     fn handle_collect_applies_tail_lines() {
         run_async(async {
@@ -1777,6 +1872,7 @@ mod tests {
                 })),
                 output_buf: Arc::new(Mutex::new(RingBuf::default())),
                 no_change_checks: 0,
+                last_check_state: None,
             };
             ctx.supervisor
                 .as_ref()
@@ -1815,6 +1911,7 @@ mod tests {
                 })),
                 output_buf,
                 no_change_checks: 0,
+                last_check_state: None,
             };
             ctx.supervisor
                 .as_ref()
@@ -1862,6 +1959,7 @@ mod tests {
                 state: Arc::clone(&state),
                 output_buf,
                 no_change_checks: 0,
+                last_check_state: None,
             };
             ctx.supervisor
                 .as_ref()
@@ -2115,6 +2213,7 @@ mod tests {
                 state: Arc::clone(&state),
                 output_buf,
                 no_change_checks: 0,
+                last_check_state: None,
             };
             ctx.supervisor
                 .as_ref()

src/function/mod.rs

@@ -2409,6 +2409,19 @@ fn polyfill_cmd_name<T: AsRef<Path>>(cmd_name: &str, bin_dir: &[T]) -> String {
     cmd_name
 }
 
+// Polling tools are expected to repeat; recording them would also let them
+// break up detection of a real loop in the calls they interleave with.
+const LOOP_TRACKER_EXEMPT_TOOLS: [&str; 4] = [
+    "job__check",
+    "job__list",
+    "agent__check",
+    "agent__list_running",
+];
+
+fn is_loop_tracker_exempt(name: &str) -> bool {
+    LOOP_TRACKER_EXEMPT_TOOLS.contains(&name)
+}
+
 #[derive(Debug, Clone)]
 pub struct ToolCallTracker {
     last_calls: VecDeque<ToolCall>,
@@ -2430,6 +2443,9 @@ impl ToolCallTracker {
     }
 
     pub fn check_loop(&self, new_call: &ToolCall) -> Option<String> {
+        if is_loop_tracker_exempt(&new_call.name) {
+            return None;
+        }
         if self.last_calls.len() < self.max_repeats {
             return None;
         }
@@ -2496,6 +2512,9 @@ impl ToolCallTracker {
     }
 
     pub fn record_call(&mut self, call: ToolCall) {
+        if is_loop_tracker_exempt(&call.name) {
+            return;
+        }
         if self.last_calls.len() >= self.chain_len * self.max_repeats {
             self.last_calls.pop_front();
         }
@@ -2663,6 +2682,7 @@ mod tests {
             })),
             output_buf: Arc::new(parking_lot::Mutex::new(jobs::RingBuf::default())),
             no_change_checks: 0,
+            last_check_state: None,
         };
         let mut sup = crate::supervisor::Supervisor::new(0, 3).with_max_concurrent_jobs(4);
         sup.register(handle).unwrap();
@@ -3105,6 +3125,46 @@ mod tests {
         assert!(msg.contains("repeat_tool"));
     }
 
+    #[test]
+    fn tracker_exempt_tools_never_trip() {
+        for name in LOOP_TRACKER_EXEMPT_TOOLS {
+            let mut tracker = ToolCallTracker::default();
+            let exempt = call_with_args(name, json!({"id": "j1"}));
+            tracker.record_call(exempt.clone());
+            tracker.record_call(exempt.clone());
+            assert!(tracker.check_loop(&exempt).is_none());
+
+            let other = call_with_args("execute_command", json!({"command": "ls"}));
+            tracker.record_call(other.clone());
+            assert!(
+                tracker.check_loop(&other).is_none(),
+                "exempt calls must not count toward the repeat threshold"
+            );
+            tracker.record_call(other.clone());
+            assert!(tracker.check_loop(&other).is_some());
+        }
+    }
+
+    #[test]
+    fn tracker_exempt_interleave_does_not_mask_real_loop() {
+        let mut tracker = ToolCallTracker::default();
+        let x = call_with_args("execute_command", json!({"command": "ls"}));
+        tracker.record_call(call_with_args("job__check", json!({"id": "j1"})));
+        tracker.record_call(x.clone());
+        tracker.record_call(call_with_args("job__check", json!({"id": "j1"})));
+        tracker.record_call(x.clone());
+        assert!(tracker.check_loop(&x).is_some());
+    }
+
+    #[test]
+    fn tracker_non_exempt_behavior_unchanged() {
+        let mut tracker = ToolCallTracker::default();
+        let c = call_with_args("fs_cat", json!({"path": "a.txt"}));
+        tracker.record_call(c.clone());
+        tracker.record_call(c.clone());
+        assert!(tracker.check_loop(&c).is_some());
+    }
+
     #[test]
     fn prefix_constants_are_correct() {
         assert_eq!(TODO_FUNCTION_PREFIX, "todo__");

src/function/supervisor.rs

@@ -1635,6 +1635,7 @@ mod tests {
             })),
             output_buf: Arc::new(Mutex::new(RingBuf::default())),
             no_change_checks: 0,
+            last_check_state: None,
         }
     }
 

src/supervisor/mod.rs

@@ -67,8 +67,8 @@ pub struct JobHandle {
     pub abort_signal: AbortSignal,
     pub state: Arc<Mutex<JobState>>,
     pub output_buf: Arc<Mutex<RingBuf>>,
-    #[allow(dead_code)]
     pub no_change_checks: u32,
+    pub last_check_state: Option<(JobStatus, u64)>,
 }
 
 impl JobHandle {
@@ -159,6 +159,13 @@ impl Supervisor {
         }
     }
 
+    pub fn job_mut(&mut self, id: &str) -> Option<&mut JobHandle> {
+        match self.handles.get_mut(id) {
+            Some(TaskHandle::Job(handle)) => Some(handle),
+            _ => None,
+        }
+    }
+
     pub fn jobs(&self) -> impl Iterator<Item = &JobHandle> {
         self.handles.values().filter_map(|handle| match handle {
             TaskHandle::Job(handle) => Some(handle),
@@ -392,6 +399,7 @@ mod tests {
             })),
             output_buf: Arc::new(Mutex::new(RingBuf::default())),
             no_change_checks: 0,
+            last_check_state: None,
         }
     }