Module persistent 

PersistentSubprocessController: manages agent CLI as a long-running process with bidirectional NDJSON streaming via stdin/stdout.

Architecture: A single CLI process is spawned on first message and kept alive for the entire session. User messages are written as NDJSON lines to stdin without closing it. This enables mid-turn input (redirecting the agent while it is still processing).

State machine: INIT ─(first message)─> RUNNING ─(idle between turns)─> RUNNING RUNNING ─(kill/stop)─> DONE RUNNING ─(process crash)─> DONE (auto-restart possible via session_id)

I/O model (3 async tasks per session):

1. stdin_writer: mpsc channel → process stdin (NDJSON lines)
2. stdout_reader: process stdout → .jsonl persistence + WPS blockfile events
3. process_waiter: wait for exit, update status

Structs

PersistentInner 🔒

Inner state protected by mutex.

PersistentSpawnConfig

Configuration for spawning the persistent process.

PersistentSubprocessController

PersistentSubprocessController keeps a long-running CLI process alive, sending user messages as NDJSON lines on stdin.

Constants

BLOCK_CONTROLLER_PERSISTENT

Controller type constant.

PERSISTENT_OUTPUT_SUBJECT

WPS file subject name for persistent subprocess output.