Add heuristic fallback for skill selection when pr-triage sub-agent fails

[Copilot]

Step 3 of mattpocock-skills-reviewer.md hard-depended on the pr-triage sub-agent returning parseable JSON, so a single flaky, timed-out, or malformed sub-agent call failed the entire run (success rate fell from 100% to 54.5%).

Changes

• Step 3 fallback branch — on error, timeout, empty output, or unparseable JSON: retry at most once, log one line, then derive the selection locally. Explicitly does not abort.
• Deterministic heuristic table — maps changed file paths and PR title/body to the same change_type / recommended_skills vocabulary the sub-agent emits. Rows are matched top-down, first match wins, with mixed_unclear → /codebase-design + /tdd as the catch-all.
• high_impact_files fallback — largest non-generated changed files by additions + deletions from the already pre-fetched pr-meta.json; key_signals empty. The review body notes when the fallback path was taken.
• Step 4 wording — now reads "the Step 3 result" rather than naming pr-triage directly, so both paths flow through identically.
• Recompiled mattpocock-skills-reviewer.lock.yml (body hash only; the prompt body is not embedded in the lock).

The heuristic reuses data already on disk, so the fallback adds no new tool calls or network dependencies.

| Signal in the changed file paths | `change_type` | `recommended_skills` |
| --- | --- | --- |
| Only `*.md`, `docs/**`, `.changeset/**` | `documentation` | `/grill-with-docs` |
| Only test files (`*_test.go`, `*.test.*`, …) | `tests_only` | `/tdd` |
| Title/body mentions fix/bug/regression/panic/crash | `bug_fix` | `/diagnosing-bugs`, `/tdd` |
| … | | |
| Anything else | `mixed_unclear` | `/codebase-design`, `/tdd` |

• Fixes [deep-report] Matt Pocock Skills Reviewer: add fallback when pr-triage sub-agent call fails or returns invalid JSON #52519

[github-actions]

PR Triage\n\n- Category: bug\n- Risk: low\n- Priority: medium\n- Score: 52/100 (impact 35 + urgency 10 + quality 7)\n- Recommended action: batch_review\n

Generated by 🔧 PR Triage Agent · auto · 62.8 AIC · ⌖ 2.76 AIC · ⊞ 7.8K · ◷

[github-actions]

🎯 Excellent Resilience Fix

Thanks for addressing the Matt Pocock Skills Reviewer reliability regression! This PR adds smart fallback logic when the pr-triage sub-agent times out or returns invalid JSON—directly solving the 54.5% success rate issue documented in #52519.

What I liked:

• ✅ Deterministic heuristic — The file-path and title-matching logic reuses the same vocabulary as the sub-agent, ensuring consistent behavior whether the fallback triggers or not.
• ✅ Zero new dependencies — The fallback reuses pre-fetched data already on disk (pr-meta.json), adding no network calls or tool overhead.
• ✅ Clear documentation — The heuristic table in the PR body makes the fallback strategy immediately understandable.
• ✅ Graceful degradation — Retries once, then proceeds with the local heuristic rather than aborting the entire run.

Coverage: The changes are tightly focused—updates to Step 3 wording and the lock file reflect the new logic without sprawl. A solid, targeted fix that should restore reliability without introducing new risk.

🚀 This looks ready for merge!

Generated by ✅ Contribution Check · auto · 55.5 AIC · ⌖ 4.15 AIC · ⊞ 8.8K · ◷

[github-actions]

PR Triage

• Category: feature
• Risk: low
• Priority: low (score: 34/100)
• Score breakdown: impact 12/50, urgency 8/30, quality 14/20
• Recommended action: batch_review
• Batch: small-features-tests-cluster

Automated triage by PR Triage Agent.

Generated by 🔧 PR Triage Agent · auto · 64.3 AIC · ⌖ 2.94 AIC · ⊞ 7.8K · ◷

[github-actions]

PR Triage

Category: feature  |  Risk: low  |  Score: 26/100

Score breakdown

• Impact: 12/50
• Urgency: 8/30
• Quality: 6/20

Recommended action: defer

Draft, no reviews yet, meta-tooling improvement — low urgency.

Generated by 🔧 PR Triage Agent · auto · 68.2 AIC · ⌖ 10.7 AIC · ⊞ 7.8K · ◷

[pelikhan]

@copilot resolve the merge conflicts on this branch.

[Copilot]

Pull request overview

Adds a local heuristic fallback so triage failures no longer abort skills-based PR reviews.

Changes:

• Adds fallback skill selection and high-impact file ranking.
• Generalizes Step 4 to consume either triage or fallback results.
• Recompiles workflow metadata.

Show a summary per file

File	Description
.github/workflows/mattpocock-skills-reviewer.md	Defines fallback triage behavior and heuristics.
.github/workflows/mattpocock-skills-reviewer.lock.yml	Updates the generated body hash.

Review details

💡 Add a code-review agent skill for context-aware, tailored reviews. Learn more in the docs.

• Files reviewed: 2/2 changed files
• Comments generated: 1
• Review effort level: Balanced

[Copilot]

@copilot resolve the merge conflicts on this branch.

Resolved in 72b1b16 (merge) and 4ad6e3d (recompile). The only conflict was in the generated .lock.yml; the .md source merged cleanly and the lock file was regenerated from it.