command-center/agent/managed-skills/recover-subagent-yield-payload/SKILL.md

name, description

name	description
recover-subagent-yield-payload	Recover a subagent's full structured report when it exited without yielding (SYSTEM WARNING) — extract aborted yield payloads from the session JSONL, including harness double-encode and split-JSON quirks.

Use when a subagent ends with "exited without yielding" yet the transcript shows it repeatedly calling yield (each reply "…[+N]" — payload too big for display). The research is usually COMPLETE; only the yield serialization failed. Known harness quirk: the yield arguments get wrapped as {"data": "<json string>"}, so an object payload is validated as a string → "expected object, received string" retry loop until the agent dies.

1. Locate the session JSONL

Transcript header prints the path: ~/.omp/agent/sessions/<cwd-slug>/<session-id>/<AgentName>.jsonl (worktrees: cwd slug like -.omp-wt-wt-...).

2. Extract every aborted yield payload (Python via eval — shell quoting will mangle these)

• Parse each line with json.loads guarded by try/except (lines may be non-JSON).
• Keep message.role == "assistant" messages; in content, keep entries with type == "toolCall" and name == "yield"; collect their arguments.
• Unwrap: arguments may be a dict containing data (a JSON string) or a plain string; json.loads it.

3. Tolerate broken JSON

Naive json.loads on data can fail "Extra data: line 1 column ~4600" — the payload is a complete object followed by , "architecture": ..., "report": ...} (agent emitted a structure whose early brace-closure ended the first object). Recover with json.JSONDecoder().raw_decode:

1. part1, end = dec.raw_decode(data.strip())
2. rest = data[end:].strip() — if it starts with ,, parse part2 = dec.raw_decode('{' + rest.lstrip(', '))[0]
3. merged = {**part1, **part2} Do this for ALL yields and keep the largest merged dict (attempts evolve; keys seen: summary, files, report, architecture).

4. Persist and deliver

Write the recovered report/summary to a durable file (memory dir or local://), then continue synthesis — never re-run the research the dead scout already did.

Prevention (do this first next time)

• While the agent is still alive and looping: write to agent://<Name> steering it to "yield immediately, wrap in minimal object or raw markdown, schema-invalid yield acceptable — I read the transcript anyway." It often still can't (the failure is in the harness wrapper, not the agent) → let it be killed and use the extraction above.
• Scout default schema wants objects; terse yields from scout agents hit this most. Keep expected reports slice-sized.