The parent-chat suppression gate (afee35700e) keyed on evt task_id
starting with 'sa-'. But terminal_tool stamps ProcessSession.task_id
with the COLLAPSED container key from _resolve_container_task_id()
('default' or the session key — subagents intentionally share the
parent's container), so real child-spawned background processes carried
task_id='default' and their completion/watch notifications walked
straight past the gate into the parent conversation.
Fix: ProcessSession gains owner_task_id (the RAW spawning task id),
stamped by both spawn paths (spawn_local/spawn_via_env) from
terminal_tool's raw task_id, carried on every queued event
(completion, watch_match, watch_disabled, overflow), round-tripped
through the crash checkpoint, and used by both the drain suppression
gate and the attribution formatter (task_id remains the fallback so
synthetic/legacy events keep working).
Live repro: on origin/main a simulated subagent completion event with
the collapsed key was delivered to the parent drain (leak); on this
branch it is suppressed, parent-owned events still deliver, and
surface_child_process_notifications=true restores delivery with
attribution. 4 new regression tests fail on origin/main, pass here.
Background processes started by subagents (task_id sa-*) route their
notify_on_complete / watch_pattern notifications to the parent
conversation (b95ec1cb5) because anything outliving the child needs a
durable consumer. In practice these 'npm ci finished' walls are noise
mid-conversation — the child's consolidated delegation result is the
deliverable.
- New config key delegation.surface_child_process_notifications
(default false = suppress). Flag true restores the previous behavior
exactly (delivery with subagent attribution line).
- drain_notifications drops (never requeues) completion/watch_match/
watch_disabled events whose task_id starts with 'sa-' when the flag
is false, logging at debug with session_id+task_id for diagnosis.
Requeueing would pin them forever — children never drain notifies.
- async_delegation events are NEVER suppressed (they ARE the result).
- watch_disabled emitters now carry task_id so sa- sessions' safety
events follow the same suppression as their other events.
- Config read errors fall back to the default (suppress) and never
crash the drain loop.
- Docs: delegation.md + configuration.md.
Control path: delegate_task(action=list/steer/stop) resolved ownership
purely through the _delegate_parent_ref weakref identity chain. The CLI
rebuilds its AIAgent mid-session (self.agent = None on route-signature
change, credential refresh, /model, MoA one-shots), so a running child's
chain pointed at a dead object and the child went invisible/unsteerable
while completion delivery (durable session-id routed) still worked.
Observed live 2026-08-17: deleg_88454b70 / sa-0-dc0100f4.
Fix: register each child with the owning conversation's durable session
id (owner_agent_session_id, the same spine delivery routes by) and add a
second ownership tier that matches it against the calling parent's
session_id with compression-lineage resolution on both sides. Foreign
sessions still fail closed.
Presentation path: background processes started BY a subagent (task_id ==
subagent_id) route their notify_on_complete notifications to the parent
conversation by design, but arrived as anonymous raw output walls. The
formatter now resolves the task_id against the live + recently-finished
subagent registry (bounded retention survives child completion) and adds
a provenance line (subagent id, delegation id, goal snippet), trimming
the output tail for subagent-owned processes. Parent-owned process
notifications are byte-identical to before.
delegate_task gains a control plane: action='list' / 'steer' / 'stop'
let the parent agent see, redirect, and early-stop its own running
subagents mid-flight — the model-facing counterpart of the TUI's
delegation.pause / subagent.interrupt / subagent.steer RPCs.
- action='list': live children of this conversation's spawn tree
(ids, goal, status, running_seconds, accepting_steer, live
transcript path). Ownership is enforced via a _delegate_parent_ref
weakref chain stamped at child build time, so a conversation can
only control its own descendants, never a sibling tree.
- action='steer': queues text into a running child via the existing
steer_subagent() registry path (delivered at the child's next tool
boundary; missed steers surface as missed_steer in the completion).
- action='stop': interrupt_subagent() — child stops at its next
iteration boundary, partial result still re-enters as a completion.
- Spawn dispatch response now includes subagent_ids + control hint.
- Control actions run synchronously (never backgrounded) and bypass
the spawn pause gate and depth limit; they also never consume the
per-turn subagent spawn cap, and remain usable once the cap is hit
(that is when stop matters most).
- Small-model robustness (found live with gpt-5.4-mini on Nous
Portal): tasks=[] alongside goal no longer trips the "Batch mode
requires at least 2 tasks" gate — treated as single-goal.
- CLI display: control calls render as "steer sa-…" / "list" instead
of an empty goal.
Live-tested E2E on Nous Portal (fable-5 + gpt-5.4-mini): full
spawn→list→steer→stop cycle, plus a steer-efficacy run where the
child acked the steer mid-essay and switched topics before finishing.
Teknium