- Agent runtime: `agents.defaults.timeoutSeconds` default 172800s (48 hours); enforced in `runEmbeddedAgent` abort timer.

- Cron runtime: isolated agent-turn `timeoutSeconds` is owned by cron. The scheduler starts that timer when execution begins, aborts the underlying run at the configured deadline, then runs bounded cleanup before recording the timeout so a stale child session cannot keep the lane stuck.

- Session liveness diagnostics: with diagnostics enabled, `diagnostics.stuckSessionWarnMs` classifies long `processing` sessions that have no observed reply, tool, status, block, or ACP progress. Active embedded runs, model calls, and tool calls report as `session.long_running`; owned silent model calls also stay `session.long_running` until `diagnostics.stuckSessionAbortMs` so slow or non-streaming providers are not reported as stalled too early. Active work with no recent progress reports as `session.stalled`; owned model calls switch to `session.stalled` at or after the abort threshold, and ownerless stale model/tool activity is not hidden as long-running. `session.stuck` is reserved for recoverable stale session bookkeeping, including idle queued sessions with stale ownerless model/tool activity. Stale session bookkeeping releases the affected session lane immediately after recovery gates pass; stalled embedded runs are abort-drained only after `diagnostics.stuckSessionAbortMs` (default: at least 5 minutes and 3x the warning threshold) so queued work can resume without cutting off merely slow runs. Recovery emits structured requested/completed outcomes, and diagnostic state is marked idle only if the same processing generation is still current. Repeated `session.stuck` diagnostics back off while the session remains unchanged.

- Provider HTTP request timeout: `models.providers.<id>.timeoutSeconds` applies to that provider's model HTTP fetches, including connect, headers, body, SDK request timeout, total guarded-fetch abort handling, and model stream idle watchdog. Use this for slow local/self-hosted providers such as Ollama before raising the whole agent runtime timeout, and keep the agent/runtime timeout at least as high when the model request needs to run longer.