opencode run teardown race after session.idle can create empty continuation assistant turn ("parts": [])

[twm-dynamo]

Summary

In non-interactive opencode run, ULW/Ralph continuation can be injected after session.idle while run teardown/disposal is already starting. The second loop turn may be created with an empty assistant payload ("parts": []).

This is reproducible with /ulw-loop ... --max-iterations=2 under both --strategy=continue and --strategy=reset.

Environment

• OpenCode CLI: 1.2.14
• oh-my-opencode plugin: 3.8.5
• OS: Linux

Reproduction

opencode run "/ulw-loop Write TRACE_TWICE and do not promise completion --max-iterations=2"
opencode run "/ulw-loop Write TRACE_TWICE_RESET and do not promise completion --max-iterations=2 --strategy=reset"

Then inspect the session:

opencode session list --format json -n 3
opencode export <session_id> > /tmp/<session_id>.json

Expected

• If continuation is injected, the continuation assistant turn should contain a non-empty response payload.
• If run mode is intentionally single-pass, continuation should not be injected.

Actual

• Continuation directive is injected for loop 2.
• A follow-up assistant message exists but has empty content ("parts": []).

Evidence

Exported sessions (directive present + empty assistant payload)

• /tmp/ses_368d1cd6affeagO950PZdu6tid.json:279
• /tmp/ses_368d1cd6affeagO950PZdu6tid.json:314
• /tmp/ses_368d192b2ffeyCZLYWUS8MUyo8.json:295
• /tmp/ses_368d192b2ffeyCZLYWUS8MUyo8.json:330

Trace ordering (idle/dispose timing overlaps continuation enqueue)

• /tmp/ulw_trace_run.log:360
• /tmp/ulw_trace_run.log:364
• /tmp/ulw_trace_run.log:365
• /tmp/ulw_trace_run.log:382
• /tmp/ulw_trace_run.log:501

Related runtime signal during continuation startup

• /tmp/ulw_trace_run.log:487

Working hypothesis

session.idle continuation enqueue and run-mode disposal are not serialized, allowing continuation to be posted during teardown and resulting in a partial second turn.

Local mitigation (plugin-side, not core fix)

Continuation hooks were disabled in run mode in local plugin bundle:

• /home/wagner/.config/opencode/node_modules/oh-my-opencode/dist/index.js:58415
• /home/wagner/.config/opencode/node_modules/oh-my-opencode/dist/index.js:58488
• /home/wagner/.config/opencode/node_modules/oh-my-opencode/dist/index.js:58808
• /home/wagner/.config/opencode/node_modules/oh-my-opencode/dist/index.js:58812
• /home/wagner/.config/opencode/node_modules/oh-my-opencode/dist/index.js:58838

This avoids partial loop behavior in run mode but does not address runtime sequencing.

Requested core fix

1. Serialize run teardown with post-idle continuation enqueue.
2. If continuation is posted, defer disposal until that turn reaches a terminal state (completed/failed/rejected).
3. If run mode disallows continuation, reject/skip enqueue before posting the directive.

Acceptance criteria (testable)

1. Running /ulw-loop ... --max-iterations=2 in opencode run never produces continuation assistant messages with "parts": [].
2. Behavior is deterministic in both --strategy=continue and --strategy=reset.
3. Exactly one mode is enforced per run:
   • continuation allowed: directive is injected and continuation response is non-empty, or
   • continuation disallowed: no continuation directive is injected.
4. A regression test covers the idle->dispose sequencing case where continuation posting and teardown are concurrent candidates.

[twm-dynamo]

Adding inline evidence excerpts so triage does not depend on my local /tmp files.

Observed in exported sessions:

/tmp/ses_368d1cd6affeagO950PZdu6tid.json:279
  "ultrawork [SYSTEM DIRECTIVE: OH-MY-OPENCODE - RALPH LOOP 2/100] ..."

/tmp/ses_368d1cd6affeagO950PZdu6tid.json:314
  "parts": []

/tmp/ses_368d192b2ffeyCZLYWUS8MUyo8.json:295
  "ultrawork [SYSTEM DIRECTIVE: OH-MY-OPENCODE - RALPH LOOP 2/100] ..."

/tmp/ses_368d192b2ffeyCZLYWUS8MUyo8.json:330
  "parts": []

Trace ordering excerpt:

/tmp/ulw_trace_run.log:364  service=bus type=session.idle publishing
/tmp/ulw_trace_run.log:365  service=default directory=/home/wagner disposing instance
/tmp/ulw_trace_run.log:382  service=server method=POST path=/session/.../message request
/tmp/ulw_trace_run.log:396  service=session.prompt step=0 sessionID=... loop
/tmp/ulw_trace_run.log:503  service=state key=/home/wagner state disposal completed

This matches the report: continuation directive appears, then a continuation assistant turn is created with empty payload (parts: []).