Watch Pr Agent Skill

Watch PR (Token-Conscious)

Watch a PR's reviews, comments, and CI with a background watcher that

wakes Claude ONLY on real events — no foreground sleep loops, no context

bloat. The watcher polls quietly in its own process; nothing enters

context until something genuinely changed.

Usage

/phx:watch-pr 42                 # watch reviews + comments + checks
/phx:watch-pr 42 --checks-only   # CI only (delegates to gh pr checks --watch)
/phx:watch-pr 42 --fix           # on actionable review, draft fixes too
/phx:watch-pr 42 --codex         # + request Codex cloud review, loop until clean
/phx:watch-pr 42 --codex --codex-rounds 2   # cap re-review rounds (default 3)

Iron Laws

• NEVER foreground-poll with sleep in the session — use the

background watcher (Monitor / run_in_background). Foreground polling

bloats context and straddles the 5-min cache TTL

• Deltas ONLY enter context — never dump full gh JSON. The watcher

emits one-line events; read .claude/watch/pr-{n}.jsonl on demand

• Silence is not success — the watcher MUST emit on PR closed/merged,

CI failure, repeated gh errors, and watchdog timeout — not just "new

comment". A silent watcher looks identical to a hung one

• NEVER auto-post replies or auto-push — hand off to /phx:pr-review

for responses; show drafts and get approval. ONE exception: passing

--codex IS the consent to post the @codex review trigger comment

(and its per-round re-requests) — nothing else is ever auto-posted

• Bound every watch — default MAX_DURATION 3600s (7200s with

--codex); always stop on terminal state. Codex rounds are bounded by

--codex-rounds (default 3) — each round costs cloud quota

Workflow

Step 1: Parse Arguments

Extract PR number (from number or URL — URL also yields the repo). Detect

--checks-only / --fix / --codex / --codex-rounds N. Baseline

timestamp = now; events are "new since baseline", so old reviews don't

re-fire.

With --codex, the default is to POST @codex review — the flag IS

that consent (Iron Law 4). Skip the trigger ONLY when the connector bot

(chatgpt-codex-connector[bot]) has itself reacted to / reviewed the

current head SHA. The repo's CI "Codex" check and any local codex exec /

/phx:review --codex / /phx:codex-loop run are DIFFERENT mechanisms from

the GitHub connector — they NEVER satisfy the skip. When unsure, post. The

connector auto-registers PRs on ready (its absence surfaces later as

codex_timeout), so check ITS reactions before posting a redundant trigger:

HEAD_AT=$(gh api "repos/{owner}/{repo}/commits/$(gh pr view {n} --json headRefOid -q .headRefOid)" --jq .commit.committer.date)
BOT=$(gh api "repos/{owner}/{repo}/issues/{n}/reactions" | jq -r --arg t "$HEAD_AT" \
  '[.[] | select(.user.login == "chatgpt-codex-connector[bot]" and .created_at >= $t) | .content] | unique | join(",")')

(gh api --jq accepts no --arg — pipe through standalone jq.)

Definitive check first: a connector-bot comment or review containing

Reviewed commit: {sha} that matches the current head sha means that

state IS reviewed (clean if it says "Didn't find any major issues") —

trust it over timestamps, which are client-set and can skew. Then:

| Connector-bot signal on current head | Action |

|-------------------------------|--------|

| +1 reaction | Connector already reviewed this head clean — no trigger, no codex round; watch CI/humans only |

| eyes + a codex review already submitted since $HEAD_AT | Findings already posted — skip the watch; run the codex_review action (Step 3) now |

| eyes only | Review in flight — do NOT post; export WATCH_CODEX=1 WATCH_CODEX_SINCE=$HEAD_AT (no trigger id) and watch |

| none (or reactions predate head) | Post the trigger and capture its id: |

TRIGGER_ID=$(gh api --method POST "repos/{owner}/{repo}/issues/${PR}/comments" \
  -f body="@codex review" --jq '.id')

Export WATCH_CODEX=1 WATCH_CODEX_TRIGGER_ID=$TRIGGER_ID to the watcher

env and set MAX_DURATION 7200. Round counter starts at 1.

Step 2a: --checks-only Path

No custom poller needed — gh pr checks --watch blocks until all checks

finish, then exits. Run via Bash with run_in_background: true:

gh pr checks {n} --watch --fail-fast --interval 10

Exit code is the signal: 0 = pass, 1 = fail, 8 = pending. On exit,

report the conclusion; on failure, offer /phx:investigate with the

failing job log (gh run view {run-id} --log-failed).

Step 2b: Full Watch Path

Start the Monitor tool (preferred — streams each event line back) on:

${CLAUDE_SKILL_DIR}/scripts/watch-pr.sh {n} reviews,comments,checks

Monitor is a deferred tool — load its schema FIRST via ToolSearch

(select:Monitor); calling it blind fails with InputValidationError

(params are command, description, timeout_ms, persistent — do

not invent others). Set timeout_ms = MAX_DURATION × 1000.

Where Monitor is unavailable

(Bedrock/Vertex/Foundry), run the same script via Bash

run_in_background: true — it exits on the first terminal event instead.

Stay idle or keep working until an event lands.

Step 3: React Per Event

| Event | Action |

|-------|--------|

| review / comment (actionable) | Summarize the delta; with --fix draft fixes + mix compile && mix test; route reply drafting to /phx:pr-review {n} |

| check conclusion failure | Offer /phx:investigate on the failing job |

| codex_ack | Note "codex is reviewing (~15–20 min on large PRs)"; keep waiting |

| codex_review | Stop the watcher. Run /phx:pr-review {n} --bots-only (fix → reply → resolve; user approves and pushes). If rounds < --codex-rounds: post @codex review again, restart watcher with the new trigger id, round+1. Else: report remaining findings, stop |

| codex_clean | Codex is clean (👍 reaction OR a "Didn't find any major issues" bot comment). If checks also green → terminal success "codex + CI clean"; else keep watching CI |

| codex_timeout | Inform: repo likely lacks the Codex connector; continue as a plain watch |

| merged / pr_closed / watchdog / watch_error | Stop, report final state |

A codex_review whose /phx:pr-review --bots-only fetch finds zero

unresolved codex threads also counts as clean (summary-only review).

Step 4: Stop

The watcher self-terminates on terminal states. To stop early: TaskStop

the background task or cancel the monitor.

Integration

push / open PR → /phx:watch-pr {n} ──(new review)──► /phx:pr-review {n}
                              ├──────(CI fail)─────► /phx:investigate
                              ├──(--codex: codex_review)─► /phx:pr-review --bots-only → push → re-request → watch (≤3 rounds)
                              ├──(--codex: codex_clean + CI green)─► done: codex + CI clean
                              └──────(merged)──────► done

References

• ${CLAUDE_SKILL_DIR}/references/watcher-mechanics.md — cache TTL math, Monitor vs run_in_background vs ScheduleWakeup, rate-limit notes