---
name: recover-subagent-yield-payload
description: "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.