Idle session release

What it is

What: A cross-platform feature that periodically releases (kills) the persistent claude CLI process of a session that finished its turn and has been waiting on you past a threshold — reclaiming all of its RAM (~250–450 MB each), not just trimming the working set. The conversation stays on screen (it's stored by Omniscio, not the process); your next message transparently re-spawns the session via --resume, so the only difference is a slightly longer first reply after a long idle. On by default.

Setting: idleSessionReleaseMinutes (number, default 15, 0 = disabled) — Settings → Performance, "Release idle sessions to reclaim more RAM". Hard kill switch: AMC_DISABLE_IDLE_RELEASE=1.

A persistent Claude CLI child stays resident across turns (so MCP servers and instant follow-ups survive). A session you got a reply from and walked away from can hold 250–450 MB indefinitely; with many such sessions that is gigabytes of pure waste. Releasing the process reclaims all of it, and the next message brings it right back.

This is the harder/later sibling of the Windows-only working-set trim (wsTrimIdleMinutes): trim de-faults pages but keeps the process alive; release frees the whole process. Releasing after 15 min costs nothing extra — a session idle that long has already lost its short-lived prompt cache, so its next reply would reload regardless.

Where to find it

There is nothing to open and nothing to switch on — it runs on its own. The only surface is the session pane itself, where a released session's next message takes a moment longer while it comes back.

How it behaves

How it works

A 60-second scheduler (idle-release-scheduler.ts) asks processManager.releaseIdleProcesses(thresholdMs, now) to kill the persistent process of every eligible session. The kill is UI-silent and leaves the session in the already-handled "dead-persistent" state (childProcess=null, receivedResult=true); the next user message hits the dead-persistent guard in user-message-router.ts → the auto-resume branch in session-service.ts, which re-spawns with --resume. No new resume code, no new visible session state.

Eligibility (the pure isEligibleForIdleRelease predicate) releases a session ONLY when ALL hold: it has a live process · the current turn has completed (receivedResult — turn completeness, not the running status string) · no recovery is in flight · it has not armed its own wait · no subagent is inside its live patience window · no background command is still live · the DB row has NO pending action · it's been idle ≥ the threshold by lastAgentMessageAt.

What is never released

• A session waiting on a question or a plan-approval (pendingAction set) — its answer is delivered to the live process's stdio control channel, so it keeps its process.
• A session that is mid-turn — judged by turn completeness (receivedResult), never by the running status string — recovering (auth / rate-limit / respawn / mid-turn-disconnect), holding a genuine prose wait or ScheduleWakeup (deferredWork of any kind other than a [[OMNISCIO_HIBERNATE]] hold), with a subagent inside its live patience window (hasLiveSubagentWindow + SUBAGENT_PATIENCE_MS), or with a background command still live.
• A [[OMNISCIO_HIBERNATE]] hold is NOT a refusal (2026-09-27). It shares kind: 'agent_prose_wait' with a genuine prose wait, but its timer is a main-process setTimeout, so killing the process does not lose it — the gate now tells the two apart by pattern id (isHibernationHold) and admits the hibernation hold. A genuine prose wait still refuses.

Scope / no-op paths

• idleSessionReleaseMinutes <= 0 OR AMC_DISABLE_IDLE_RELEASE=1 → the scheduler tick returns early (feature off).
• Cross-platform — process kill works everywhere (unlike the Windows-only trim).
• No pre-warm on focus (yet): the reload happens on your next message ("a little longer in the background"), not when you open the session.

For agents

Source

• src/main/process/idle-release-eligibility.ts — the pure eligibility predicate.
• src/main/process/process-manager.ts — releaseIdleProcesses / getEligibleForRelease.
• src/main/process/process-manager-idle-release.ts — hasLiveSubagentWindow / SUBAGENT_PATIENCE_MS, the subagent patience window.
• src/main/services/idle-release-scheduler.ts — the 60s scheduler + kill switch + telemetry.

Tests

• tests/unit/process/idle-release-eligibility.test.ts — every release/skip rule + the idle boundary.
• tests/unit/services/idle-release-scheduler.test.ts — threshold conversion, kill switch, observability, lifecycle.

Related

• session-memory-paging.md — the Windows working-set CAP (a different lever: pages a busy session to disk instead of releasing an idle one's process).
• Contract: .claude/memory/contracts/idle-session-release-contract.md.