loopd: scheduler yields to a held subagent

Co-Authored-By: ornith-1.5-35b-a3b <agent@wntrmute.dev>

crates/loopd/src/channel.rs

@@ -59,6 +59,12 @@ impl Context {
         drop(busy);
         Ok(Held { ctx: self, id })
     }
+
+    /// True when any held session id starts with `prefix` (`sub-` for a live child).
+    pub fn holds_prefix(&self, prefix: &str) -> bool {
+        let busy = self.busy.lock().unwrap_or_else(|p| p.into_inner());
+        busy.iter().any(|id| id.as_str().starts_with(prefix))
+    }
 }
 
 /// While a turn runs, the session is in the busy set. The guard holds only an immutable borrow of

crates/loopd/src/scheduler.rs

@@ -43,6 +43,9 @@ impl Scheduler {
             self.leftovers_closed = true;
         }
         self.heartbeat(ctx, now, &mut work);
+        if ctx.holds_prefix("sub-") {
+            return work;
+        }
 
         let jobs_dir = ctx.cfg.paths.home.join("jobs");
         let runs_path = jobs_dir.join("runs.jsonl");
@@ -184,6 +187,9 @@ impl Scheduler {
         if !due {
             return;
         }
+        if ctx.holds_prefix("sub-") {
+            return;
+        }
 
         let id = match SessionId::new("heartbeat") {
             Ok(id) => id,

crates/loopd/tests/scheduler_subagent.rs

@@ -0,0 +1,89 @@
+//! Heartbeat and cron yield to a held subagent. Do not edit.
+
+mod support;
+
+use bxcore::{SessionId, Timestamp};
+use loopd::channel::Context;
+use loopd::llama::Client;
+use loopd::memory::NoMemory;
+use loopd::scheduler::{Scheduler, TickWork};
+use loopd::tools::Registry;
+use std::sync::Arc;
+use support::{FakeServer, Home, Reply, ScriptedPort};
+
+const CHAT: &str = "/v1/chat/completions";
+
+fn sse() -> Reply {
+    let data1 = r#"data: {"choices":[{"finish_reason":null,"index":0,"delta":{"content":"noted"}}],"id":"h","timings":{"cache_n":0,"prompt_n":10,"predicted_n":1}}"#;
+    let data2 = r#"data: {"choices":[{"finish_reason":"stop","index":0,"delta":{}}],"id":"h","timings":{"cache_n":0,"prompt_n":10,"predicted_n":1}}"#;
+    let body = format!("{data1}\n\n{data2}\n\ndata: [DONE]\n\n");
+    Reply::raw(format!(
+        "HTTP/1.1 200 OK\r\nContent-Type: text/event-stream\r\nContent-Length: {}\r\nConnection: close\r\n\r\n{body}",
+        body.len()
+    ))
+}
+
+fn ts(s: &str) -> Timestamp {
+    Timestamp::parse(s).unwrap()
+}
+
+#[test]
+fn a_held_subagent_skips_a_due_heartbeat() {
+    let home = Home::new();
+    home.write("heartbeat.md", "Look around.\n");
+    home.write("compact.md", "Summarise.\n");
+    let server = FakeServer::start();
+    let mut cfg = home.config(&server.socket);
+    cfg.heartbeat.every_s = 60;
+    cfg.heartbeat.prompt = home.dir.join("heartbeat.md");
+    server.route(CHAT, vec![sse()]);
+    let ctx = Arc::new(Context::new(
+        cfg.clone(),
+        Client::new(cfg),
+        Box::new(ScriptedPort::new(vec![])),
+        Registry::m2b(),
+        Box::new(NoMemory),
+    ));
+    let held = ctx
+        .hold(SessionId::new("sub-mm-thread-1").unwrap())
+        .expect("hold");
+    let mut sched = Scheduler::new(ts("2026-10-03T07:00:00.000Z"));
+    let work = sched.tick(&ctx, ts("2026-10-03T07:01:00.000Z"));
+    assert!(work.is_empty(), "{work:?}");
+    assert!(server.requests_to(CHAT).is_empty());
+    drop(held);
+    let work = sched.tick(&ctx, ts("2026-10-03T07:02:00.000Z"));
+    assert_eq!(work, vec![TickWork::Heartbeat]);
+    assert_eq!(server.requests_to(CHAT).len(), 1);
+}
+
+#[test]
+fn a_held_subagent_skips_a_due_cron_job() {
+    let home = Home::new();
+    home.write("compact.md", "Summarise.\n");
+    home.write(
+        "jobs/mail.toml",
+        "schedule = \"0 7 * * *\"\nprompt = \"Check mail.\"\n",
+    );
+    let server = FakeServer::start();
+    let cfg = home.config(&server.socket);
+    server.route(CHAT, vec![sse()]);
+    let ctx = Arc::new(Context::new(
+        cfg.clone(),
+        Client::new(cfg),
+        Box::new(ScriptedPort::new(vec![])),
+        Registry::m2b(),
+        Box::new(NoMemory),
+    ));
+    let held = ctx
+        .hold(SessionId::new("sub-mm-thread-1").unwrap())
+        .expect("hold");
+    let mut sched = Scheduler::new(ts("2026-10-03T06:00:00.000Z"));
+    let work = sched.tick(&ctx, ts("2026-10-03T07:00:00.000Z"));
+    assert!(work.is_empty(), "{work:?}");
+    assert!(server.requests_to(CHAT).is_empty());
+    drop(held);
+    let work = sched.tick(&ctx, ts("2026-10-03T07:00:00.000Z"));
+    assert_eq!(work.len(), 1);
+    assert!(matches!(work[0], TickWork::Job { .. }), "{work:?}");
+}

docs/implementer-log.md

@@ -6,6 +6,7 @@ reviewer adds findings under "Reviews" once per milestone.
 
 | Task | Date | Status | Gate runs | First gate | Deviations | Notes | Model |
 |---|---|---|---|---|---|---|---|
+| M6a/04-loopd-scheduler-skip | 2026-10-03 | done | 1 | pass | none | Copied the given test `crates/loopd/tests/scheduler_subagent.rs` from `docs/plans/M6a/files/`. Step 2 (`cargo test -p loopd --test scheduler_subagent`) failed as expected: both tests failed, `work` not empty (a `Heartbeat` and a `Job { name: "mail", session: "job-mail-20261003t0700" }`) and `requests_to(CHAT)` not empty while the child was held. Applied H1 in channel.rs: added `holds_prefix` after `hold`'s closing `}` inside `impl Context`, locking `busy` like `hold` and returning whether any id starts with the prefix. Applied K2 in scheduler.rs `heartbeat`: after the `if !due { return; }` block and before `SessionId::new("heartbeat")`, `if ctx.holds_prefix("sub-") { return; }`. Applied K1 in scheduler.rs `tick`: immediately after `self.heartbeat(...)` and before `jobs_dir`, `if ctx.holds_prefix("sub-") { return work; }` so leftover-close on the first tick is already done. `cargo check -p loopd` clean, no warning; `wc -l` prints 307 channel.rs, 310 scheduler.rs, both under 500. All suites pass: `scheduler_subagent` 2, `scheduler_heartbeat` 6, `scheduler_cron` 6, `scheduler_heartbeat_failed` 1. `make gate` printed `gate: ok` with 1587 tests (1585 before, plus 2). No new dependency, so `Cargo.lock` unchanged. | ornith-1.5-35b-a3b |
 | M6a/03-loopd-subagent-spawn | 2026-10-03 | done | 1 | pass | none | Copied the given test `crates/loopd/tests/subagent_spawn.rs` from `docs/plans/M6a/files/`. Step 2 (`cargo build --tests --keep-going -p loopd`) failed as expected: E0560 `Runtime` has no field `ctx`. Added `pub ctx: Option<&'a crate::channel::Context>` to `Runtime` in turn.rs R1, filled it `Some(&*ctx)` in channel.rs C1 (live turn), `Some(ctx)` in the cron and heartbeat literals in scheduler.rs S1/S2 (both already held an immutable borrow of `ctx`), and `None` in the seven test literals: support/turn.rs, compact_turn.rs (the helper and the inline one), session_slot.rs, end_to_end.rs, turn_broker.rs, tool_summary_call.rs. Replaced the stub `run` in subagent.rs with the full spawn: build `sub-<parent>-<n>` from the already-consumed `call_id.0`, overflow returns `denial_message(InvalidArguments, Some(...))` naming subagent-id without holding, then `rt.ctx` `None` and `hold Busy` and block/baseline/create errors each return `failed`, a `Create` `Exists` falls back to `open`, the child runs one `run_turn` plus `finish_turn` on `slots.background`, memory is updated, `untrusted` is read before the hold drops, and the result is `{id} completed\n{summary}` or `{id} failed`, all `Public`. Added `RUNBOOK` and the use lines the body needs. Appended `## subagent-id` to docs/runbook.md via the task's `{ echo; cat ...; }` (grep -c prints 1). `cargo check -p loopd` clean, no warning; `wc -l` prints 185 subagent.rs, 335 turn.rs, 301 channel.rs, 304 scheduler.rs, all under 500. All suites pass: `subagent_spawn` 5, `subagent_dispatch` 3, `subagent_registry` 2, `session_slot` 4, `tool_summary_call` 6, `compact_turn`, `channel`. `make gate` printed `gate: ok` with 1585 tests (1580 before, plus 5). No new dependency, so `Cargo.lock` unchanged. | ornith-1.5-35b-a3b |
 | M6a/02-loopd-subagent-dispatch | 2026-10-03 | done | 1 | pass | none | Copied the given test `crates/loopd/tests/subagent_dispatch.rs` from `docs/plans/M6a/files/`. Step 2 (`cargo build --tests --keep-going -p loopd`) failed as expected: E0599 no `Subagent` variant and E0425 no `child_id`. Added `Dispatch::Subagent { task }` in tools.rs D1, routed `subagent` in `dispatch` and `dispatch_call_tool` (D2/D3) via `crate::subagent::dispatch_args`, added the `Subagent` arm in `run_call` (turn.rs T1) calling the stub `run`, and appended `child_id`, `parse_task`, `dispatch_args` and the stub `run` to subagent.rs. `parse_task` walks every key (unknown field), requires `task`, demands a string task and a JSON object arguments, and maps errors to `denial_message(InvalidArguments, Some(&detail))`. `run` stays a compiling stub, no spawn, no `Runtime.ctx`. `cargo check -p loopd` clean, no warning; `wc -l` prints 76 for subagent.rs, 477 for tools.rs, 332 for turn.rs, all under 500. All suites pass: `subagent_dispatch` 3, `subagent_registry` 2, `tools` 11. `make gate` printed `gate: ok` with 1580 tests (1577 before, plus 3). No new dependency, so `Cargo.lock` unchanged. | ornith-1.5-35b-a3b |
 | M6a/01-loopd-subagent-registry | 2026-10-03 | done | 1 | pass | none | Copied the given test `crates/loopd/tests/subagent_registry.rs` from `docs/plans/M6a/files/`. Created `crates/loopd/src/subagent.rs` with `SUBAGENT` and `schema()` (a non-core `ToolSchema`, no `parse_task`/`dispatch_args`/`run`). Added `pub mod subagent;` after `pub mod sse;` in lib.rs (rustfmt order). Edited `m5c()` in tools.rs to push the non-core `subagent` entry after the `ask_memory` insert at index 3, so `ask_memory` stays at 3 and `subagent` is last among the non-core names; `core_schemas()` still returns only the six core names and `find("subagent")`/`find("isolated")` both hit it. `cargo check -p loopd` clean, no warning; `wc -l` prints 22 for subagent.rs and 470 for tools.rs, both under 500. All suites pass: `subagent_registry` 2, `ask_memory_tool`, `tools` 11, `baseline` 6. `make gate` printed `gate: ok` with 1577 tests (1575 before, plus 2). No new dependency, so `Cargo.lock` unchanged. | ornith-1.5-35b-a3b |