chore(agent): commit the machine tier and the doctrine text the checkout was already running

Landing blocker for #61 and #63: the deployment checkout is 12 commits behind and
`merge --ff-only` refuses while tracked paths are dirty. Discard is not available here
(workspace policy: no `checkout`/`stash` on shared state), so the dirt is committed.

- `agent/APPEND_SYSTEM.md`: the point-of-use / one-work-log / PR-link doctrine, already
  byte-identical to `origin/main` (`cmp` against the trunk blob: no difference). No new
  prose — the commit exists so the trunk merge can proceed.
- `agent/config.yml` and `agent/managed-skills/**`: the machine-live tier the heartbeat
  owns (AGENTS.md § Live-sync tiers).

`ALLOW_SECRETS=1` was used, deliberately and after auditing the staged diff by hand: the
only credential-shaped strings in it are two copies of `AKIA0000000000000EXAMPLE` — the
inert all-zero AWS example id — and they appear inside the two skill pages that teach
that exact placeholder shape. This checkout is still running the pre-#61 hook; the merged
gate (value-scoped placeholder filter, `71601f7`) exempts this value, so the refusal
dies with this landing. No `--no-verify` was used: the gate ran and its verdict is
recorded here.

Refs #61

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

@@ -1,28 +1,27 @@
 ---
 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."
+description: "Recover or salvage subagent deliverables: missing yields, payloads misrouted to xd://report_issue, and degraded TAKEN-list echoes."
 ---
 
-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.
+# Recovering subagent deliverables
 
-## 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-...`).
+Three failure modes seen with scout bulk-content tasks, in order of frequency.
 
-## 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.
+## 1. Misrouted payload: scout wrote the deliverable to `xd://report_issue`
+Symptom: yield summary says "delivered to `xd://report_issue`" instead of containing the content. That device is write-only (a bug-report channel); the response "Noted, thanks!" fooled the scout into thinking delivery worked.
 
-## 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`).
+**Salvage path (often impossible — decide fast, ≤2 probes):**
+- Transcript jsonl: `~/.omp/agent/sessions/*/*/Tan-*/Tan-*.jsonl` (glob by agent id).
+- Streamed `toolCall` blocks store only **partial arg fragments** of big writes (`arguments.content` is chunked/empty; `partialArgs` holds deltas). Reassembly of a 140-line write across ~100 fragment rows has never worked — if `content` on the toolCall rows is empty or truncated, **abandon salvage**.
+- Only reliable in-file content: final assistant text blocks — walk rows for `message.role=="assistant"`, `content[].type=="text"`, filter lines against the delivery contract regex.
 
-## 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 (put in scout prompts for bulk content):** "Return the deliverable as plain lines in your FINAL OUTPUT TEXT. NEVER write it to `xd://report_issue`, files, or eval state."
 
-## 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.
+## 2. Degenerate echo: scout returns the TAKEN/dedupe examples verbatim
+Symptom: candidate lines repeat the "already used" examples given in the prompt, in looping blocks. Write off that batch entirely — do not re-prompt (it repeats). Cover the cluster inline yourself.
+
+## 3. No yield at all (hung/force-stopped)
+`history://<agent-id>` renders the transcript but compresses tool payloads to "1 line" — useless for payloads, fine for status. Try `write agent://<id>` with a one-line re-emit instruction ("end your turn by yielding the lines verbatim; do not re-research") exactly once; if the reply is garbage, abandon.
+
+## Rule of thumb for bulk creative content
+Scouts add value for *terminology research* (search the universe's rank/offices vocabulary, 2-5 searches), not for drafting hundreds of lines — models echo, spin variants ("dune-mentat of the X" ×14), and misroute. Pattern: scout researches → parent drafts.