Implement the continuable background subagents RFC: a durable child
session with a series of Task-backed activations, each disposing its
run before the Task settles.
- dsh-subagent: rename SubagentRun.sendMessage to strict steer, drop
run-level resume, add SubagentProvider.resume dispatch via
SubagentService.resume, the continuation start field, and the
versioned model-hidden subagent/descriptor session event.
- dsh-subagent-inprocess/-spawn/-fork: publish the control-allocated
child id, append the descriptor inside the initial turn, implement
cold resume from the child's own transcript under the live parent
scope, and strict running-only steer.
- dsh-subagent-control (new): SubagentControlService owning stable
child ids, descriptor snapshot/fold/authorization, Task-backed
activation with settle-then-dispose ordering, the process-local
active-run association, and steer-or-resume sendMessage routing.
- dsh-tool-subagent: background route branches on the provider's
resume capability (continuable via the control service; one-shot
task for ACP), returning both child and task ids.
- dsh-tool-subagent-control (new): the globally named send_message
tool rendering steered/started routes.
Keyless coverage spans Task ownership and disposal ordering, running
delivery, cold follow-up, descriptor rejection and rollback, known-id
reconstruction, kill during lookup, admission races, and a new
subagent-continuable ACP snapshot scenario.
additionalProperties: false on the todo_write item schema is model-visible
(tool schemas ride the request header and the code-mode prompt types), so
the pinned ACP/headless expected outputs re-record. Keyless refresh; the
two locally-failing scenarios are this machine's known environment issues
(HOME-symlink cwd normalization, SQLite ExperimentalWarning), not the diff.
Rename the six model-facing tools pty_* -> terminal_* and align every
description, guidance section, ACP card title, and rendered result to
terminal terminology. Package and service internals keep their technical
PTY names (PtyService, "unknown PTY session", node-pty).
Harden the local backend teardown:
- a failed close is retryable: drop the memoized rejection so a later
terminal_close re-runs against the live process table
- service disposal clears the backend, reservation, and owner-cleanup
registries even when a close fails
- stop readiness polling before teardown so an in-flight send settles as
session_exit instead of a mis-inferred wait reason
- bound the sanitizer's pending buffer against unterminated escape runs
Update the tool catalog, package READMEs, the bilingual Agent Note, and the
acp/headless pty-tools snapshots to match.
