Self-extension workflow

Exact prompt and procedure the agent executes after every mistake. The agent never pushes to main directly. Every self-extension is a PR.

Five agent steps plus a search-prerequisite, from mistake to merged rule. The agent never pushes to main. Every rule that lands is CODEOWNERS-approved. This page is the contract.

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TRIGGER CONDITIONS

Five conditions. Any one of them starts the workflow.

The agent starts this workflow when any of these is met:

• A test fails and the agent wrote the faulty code.
• A code review comment corrects the agent.
• The agent realises during implementation that its first approach was wrong.
• A deployment problem occurs that the agent caused.
• The user explicitly says: "That was wrong" / "Remember this".

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STEP-BY-STEP PROCEDURE

Five steps after the search-prerequisite. Every step is mandatory before the next one.

Step 0 — Search before write

Mandatory. Duplicates in the error log destroy the signal.

Before creating a new error entry, search the existing error log:

1. Read skills/error-log/SKILL.md.
2. Search for similar errors (same category + similar context).
3. If a similar entry exists:
   - Increment its `count` field by 1.
   - Update `last_seen` to today.
   - Supplement the context if needed.
   - Do NOT create a new entry.
4. Only if no similar entry exists, continue with Step 1.

Step 1 — Analyse the error

The agent answers six questions before writing anything.

1. What exactly did I do? (concrete code/action)
2. What should I have done instead?
3. Why did I do it wrong? (false assumption, missing knowledge, carelessness)
4. Which category applies?
   - development: code error, wrong implementation
   - git: commit/branch mistake
   - deployment: deployment order, configuration
   - security: security vulnerability
   - performance: N+1, missing indexes, oversized datasets
   - domain: wrong understanding of business rules
5. How severe was the error? (critical/high/medium/low)
6. Which target file does the rule belong in?

Step 2 — Determine new error ID

Take the next number after the latest entry.

# Find last entry in error-log.md
grep "id: ERR-" skills/error-log/SKILL.md | tail -1
# Take next number: ERR-2026-004 -> ERR-2026-005

Step 3 — Formulate the entry

Action directive only. The CI verb allow-list rejects anything else.

Use the template at skills/error-log/_entry-template.md. The schema at `schemas/error-entry.json` is enforced by CI.

[!WARNING] CI GATE · verb allow-list — new_rule must start with one of Always, Never, Before, After, Prefer, Avoid, Use, Do, Ensure. Anything else is rejected.

Bad: "SQL injection is dangerous" Good: "Never concatenate user input directly into SQL queries. Always use prepared statements."

Step 4 — Determine target file

One file per category. Domain rules go to a project file, not a global one.

Error category	Target file
development	skills/code-quality/SKILL.md
git	skills/git-conventions/SKILL.md
deployment	skills/review-deployment/SKILL.md
security	skills/code-quality/SKILL.md (Security section)
performance	skills/code-quality/SKILL.md (Performance section)
domain	skills/<project>/SKILL.md

Step 5 — Insert the rule

At the end of the matching section. Reference the ERR-ID.

1. Open the target file.
2. Find the matching category section.
3. Add the new rule at the end of the section.
4. Add reference: Reference: ERR-YYYY-NNN.

Step 6 — Open a PR

Never push to main directly. The label triggers the lint-rules workflow.

git checkout -b learn/ERR-YYYY-NNN
git add skills/
git diff --cached            # MANDATORY human review step
git commit -m "learn(errors): ERR-YYYY-NNN — <short description>

Co-Authored-By: <your real name> <your-email@example.com>"
git push -u origin learn/ERR-YYYY-NNN
gh pr create --label needs-rule-review \
             --title "learn(errors): ERR-YYYY-NNN" \
             --body "Auto-generated rule. Reviewer: confirm rule wording and target file. CI \`lint-rules\` must pass."

Branch through CI gates and CODEOWNERS into a squash-merge on main.

Why a PR (not a direct commit). Four layers of gating.

Layer	What it gates	Where
lint-rules	Schema + verb allow-list + forbidden patterns	`schemas/error-entry.json`
auto-approve-rule-pr	Diff scope (skills/** — error-log entry plus the target sub-skill) and Co-Authored-By: trailer	.github/workflows/auto-approve-rule-pr.yml
Branch protection	CODEOWNERS approval for skills/error-log/	.github/CODEOWNERS
Human review	Final read of rule wording and target file	maintainer

[!NOTE] CI GATE · four-layer gating — Every rule that goes live has been seen by a human. The validator is best-effort, not airtight — see SECURITY.md Limitations section.

The commit type learn makes self-extension visible in git log --grep="learn(".

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FALSE POSITIVES IN THE VALIDATOR

When a legitimate rule must mention a forbidden pattern (e.g. preventing subprocess misuse).

1. Add the new error ID to skills/error-log/exceptions.yml:

   allow_forbidden_pattern_for:
     - ERR-YYYY-NNN  # rationale: rule must mention `subprocess` to be specific
   

2. Open the PR. CODEOWNERS approval is required for exceptions.yml changes — the bypass is auditable in git history.
3. The verb allow-list still applies even with a bypass entry.

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CONSOLIDATION LOOP

When the error log exceeds 50 entries. Manual diff review until eval framework lands.

1. Read all entries in skills/error-log/SKILL.md.
2. Group by root_cause similarity.
3. For groups with the same root cause:
   - Keep the most detailed entry.
   - Sum up all `count` values.
   - Set `last_seen` to the most recent date.
   - Delete the duplicates.
4. For entries older than 6 months with severity: low:
   - Archive (move to a comment block or separate archive file).
   - The rules derived from them remain in the sub-skills.
5. Open a PR: "chore(errors): consolidate error log (N entries merged)".

LLM-driven consolidation is non-deterministic. Until the eval framework (Phase 2 roadmap) reports a stable baseline, do consolidation manually with diff review. The threshold of 50 entries is a soft signal, not a forced rebuild.

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WHY THIS SUB-SKILL MATTERS

Self-extension as a normal version-control discipline.

The agent doesn't just fix errors — it learns from them, and every lesson is a Git commit you can review, revert, or share. The PR-flow brings the standard engineering toolkit to rule learning: deterministic validation, branch protection, CODEOWNERS approval, and a public audit trail.

Your agent's mistakes — versioned. Self-learning skills, every commit. One source, four agent runtimes. That's the loop.