docs: document idle watchdog activity pulses

2026-08-09 15:12:23 +08:00
parent 57c9e077ce
commit cf5e04f75c
3 changed files with 14 additions and 12 deletions
@@ -57,10 +57,11 @@ export function deadline(
 export interface IdleWatchdog {
  readonly signal: AbortSignal
  next<T>(iterator: AsyncIterator<T>): Promise<IteratorResult<T>>
+  pulse(): void
  [Symbol.dispose](): void
 }

-/** Arm only while one iterator `next()` is outstanding, then rearm on later demand. */
+/** Arm only while one iterator `next()` is outstanding; rearm on later demand or out-of-band activity. */
 export function idleWatchdog(
  upstream: AbortSignal | undefined,
  timeoutMs: number,
@@ -71,7 +72,7 @@ export function idleWatchdog(
 export function timeoutOf(x: AbortSignal | { reason?: unknown }, code?: string): TimeoutReason | undefined
 ```

-`deadline` fuses an upstream signal with a one-shot timer through `AbortSignal.any`, adds a typed `TimeoutReason`, and exposes disposable timer cleanup. Non-positive timeouts are an internal no-timeout sentinel for backend-owned background work; external hints pass through `clampTimeout` and must be positive and finite. Without a timer or upstream signal, the function returns a never-aborting signal with the same disposal shape. `idleWatchdog` instead requires a positive finite interval, keeps one stable fused signal for the entire stream, and arms its timer only while one iterator `next()` is outstanding; resolution disarms it, later demand rearms it, concurrent demand fails, and disposal clears the active arm. Providers translate timeout reasons into seam-specific results. `timeoutOf(signal, code)` scopes classification so an outer nested deadline is treated as upstream cancellation rather than the inner capability's timeout.
+`deadline` fuses an upstream signal with a one-shot timer through `AbortSignal.any`, adds a typed `TimeoutReason`, and exposes disposable timer cleanup. Non-positive timeouts are an internal no-timeout sentinel for backend-owned background work; external hints pass through `clampTimeout` and must be positive and finite. Without a timer or upstream signal, the function returns a never-aborting signal with the same disposal shape. `idleWatchdog` instead requires a positive finite interval, keeps one stable fused signal for the entire stream, and arms its timer only while one iterator `next()` is outstanding; resolution disarms it, later demand rearms it, and `pulse()` rearms that same outstanding demand after out-of-band transport activity. A pulse outside outstanding demand or after disposal is a no-op; concurrent demand fails, and disposal clears the active arm. Providers translate timeout reasons into seam-specific results. `timeoutOf(signal, code)` scopes classification so an outer nested deadline is treated as upstream cancellation rather than the inner capability's timeout.

 ### The division of labor

@@ -79,7 +80,7 @@ export function timeoutOf(x: AbortSignal | { reason?: unknown }, code?: string):
 |---|---|
 | Validate request hint and clamp default/max | `dsh-timeout` (`clampTimeout`) — pure arithmetic plus the shared positive-finite request contract |
 | Arm one-shot timer, abort on deadline, carry reason, fuse with upstream cancel | `dsh-timeout` (`deadline`) |
-| Arm and rearm only around outstanding iterator demand | `dsh-timeout` (`idleWatchdog`) |
+| Arm and rearm only around outstanding iterator demand, including out-of-band activity | `dsh-timeout` (`idleWatchdog`) |
 | Clear the timer | `dsh-timeout` (`[Symbol.dispose]` on either primitive) |
 | Classify the first abort reason after abort | `dsh-timeout` (`timeoutOf`) |
 | **Actually terminate the work** | the capability's implementation |
@@ -92,7 +93,7 @@ The signal only *notifies*; termination is always the listener's job, and the li

 - **web_fetch** — the tool stays validate-and-forward; the provider's hand-rolled controller + `setTimeout` + manual listener + `finally` + `signal.reason` recovery is replaced by provider-owned `deadline`/`timeoutOf`. A pre-aborted upstream signal still throws `WEB_ABORTED` up front; otherwise `fetch` runs against the fused `d.signal`, and `translateAbortOrNetwork` classifies a thrown error by the signal (`timeoutOf` → `WEB_FETCH_TIMEOUT`, else aborted → `WEB_ABORTED`, else network → `WEB_PROVIDER_ERROR`). The public error-code contract is unchanged, and `TimeoutReason` never crosses the web seam as the public error.
 - **bash** — `resolve()` clamps the request into an explicit spec. Foreground `run()` creates the deadline and passes its signal to process execution, whose existing abort listener performs the process-group kill. The executor classifies the first abort as timeout or cancellation. Background starts remain timeout-free and forward only upstream cancellation.
- **LLM adapters** — `dsh-llm-deepseek` and `dsh-llm-pi-ai` wrap actual transport iteration with `idleWatchdog`. The five-minute configured interval covers only outstanding provider demand, not time the downstream consumer spends between chunks. The stable signal reaches `fetch` or the SDK for the whole call, so timeout closes the underlying request and maps to `TIMEOUT`, while an earlier caller abort maps to `ABORTED`.
+- **LLM adapters** — `dsh-llm-deepseek` and `dsh-llm-pi-ai` wrap actual transport iteration with `idleWatchdog`. The five-minute configured interval covers only outstanding provider demand, not time the downstream consumer spends between chunks. The direct DeepSeek adapter also pulses that outstanding demand when its SSE parser observes a comment, without yielding the comment as a `StreamChunk` or writing it to the session log. The pi-ai SDK does not expose comment activity to its adapter, so that path can rearm only when the SDK yields. The stable signal reaches `fetch` or the SDK for the whole call, so timeout closes the underlying request and maps to `TIMEOUT`, while an earlier caller abort maps to `ABORTED`.

 ## Consequences

@@ -100,7 +101,7 @@ The signal only *notifies*; termination is always the listener's job, and the li
 - `SpawnSpec.timeoutMs` and `SpawnOutcome.timedOut`/`aborted` were removed rather than kept as always-zero/always-false vestiges: with `runBash` owning no timer and the executor owning classification, they were read nowhere. This is the one deviation from the literal proposal shape (which passed `timeoutMs: 0` into `runBash`); an always-0 field read by nothing is dead weight under the per-file coverage gate.
 - web_fetch shed its bespoke controller/timer/listener/reason-recovery; the classifier now keys off the deadline signal (`timeoutOf` + `aborted`) rather than the thrown error's shape, which is robust across both the request-phase reject-with-reason and the read-phase bare-`AbortError`.
 - `AbortSignal.any` and `using`/`Symbol.dispose` enter the repo for the first time here (Node ≥ 24 baseline, already met).
- Model streams now share one rearmable timer contract without turning a sliding idle interval into a total-call deadline or charging consumer think time. The primitive still only notifies; adapter tests prove their transports observe its stable signal and terminate.
+- Model streams now share one rearmable timer contract without turning a sliding idle interval into a total-call deadline or charging consumer think time. Adapters that can observe out-of-band transport activity may pulse an outstanding demand; suppressed activity remains invisible to the watchdog. The primitive still only notifies; adapter tests prove their transports observe its stable signal and terminate.

 Out of scope, named to mark the boundary: `web_search` can gain an optional model-facing `timeout_ms` once its tool-schema/snapshot coverage is planned; future ripgrep-backed fs discovery tools can consume the same provider-owned deadline shape once they exist; a `tools/execute` waterfall middleware could arm a default deadline for every tool call by driving `exec.signal` — that would be a plugin that *consumes* this library and still only notifies, the hard kill remaining each capability's job.