Agent Skills: Fix Skill

Fix Skill

Purpose

Minimal-ceremony fix workflow for bugs and technical debt. GitHub issue is optional — provide one for traceability, or describe the problem free-form.

Replaces /issue-fix. Key differences from the old skill:

• Issue number not required
• No automatic PR (opt-in with --pr)
• Cleaner ceremony: branch → fix → security scan → regression test → commit

When to Use vs Other Skills

| | /quick | /fix | /implementation | | -------- | -------------- | ----------------- | ------------------ | | Ceremony | None | Minimal | Full | | Size | Tiny (minutes) | Small-medium | Medium-large | | Type | Anything | Bug / tech debt | Feature / refactor | | Issue | Optional | Optional | Optional | | PR | No | Optional (--pr) | Yes | | Tests | No | Regression only | Full TDD |

Usage

/fix "broken login after password change"
/fix --issue 42 "auth regression on mobile"
/fix --pr "memory leak in worker queue"        # create PR after commit
/fix --issue 15 --pr "null pointer in parser"  # issue + PR

Workflow

1. Analysis

If issue provided:

gh issue view <N>

Complexity check — pick one path:

Simple fix (root cause obvious from description, ≤2 files, no security implications): → Reason through root cause directly, proceed to Step 2.

Complex fix (scope unclear, multiple files, security implications, or ambiguous cause): → Automatically enter Plan Mode:

1. Call EnterPlanMode
2. Spawn a Plan agent (model: sonnet) with all gathered context to produce:
   • Root cause analysis
   • Minimal change plan (files + rationale)
   • Regression test strategy
   • Security implications (if any)
3. Call ExitPlanMode — present plan to user, wait for approval
4. After approval, proceed to Step 2

Root cause still unclear after analysis? Stop and run /diagnose "<symptom description>" first. Return here once the investigation identifies the root cause.

2. Branch

# With issue number
git checkout -b fix/<N>-brief-description

# Without issue (free-form)
git checkout -b fix/brief-description

Check for open release branches first:

git branch -r --list 'origin/release/*' | sed 's|origin/||'

If a release branch exists, ask: "Target release branch or main?"

3. Implement

Fix following these principles:

• Minimal: touch only what's needed — resist refactoring adjacent code
• Secure: validate inputs, handle errors cleanly, no data leaks
• Defensive: null checks, proper error boundaries

4. Test

Write a regression test to verify the fix:

# Python
ruff check . && mypy .
pytest -k "test_<relevant>"  # Full suite runs on CI; locally run only relevant tests

# JS/TS
npm run lint && npm run typecheck
npm test -- --testPathPattern="<relevant>"

Test requirements:

• Bug reproduction test (confirms fix works)
• Security edge cases if the bug has security implications
• Trivial fixes: add a test case to the nearest existing test file (no new test file needed)

5. Gate

Run /security-verify scan before committing — non-negotiable per rules/security-gate.md.

6. Commit

# With issue
git commit -m "$(cat <<'EOF'
fix: <description>

Fixes #<N>
EOF
)"

# Without issue
git commit -m "fix: <description>"

7. Optional PR

Only if --pr flag or explicitly requested:

gh pr create --title "fix: <description>" --body "$(cat <<'EOF'
## Root Cause
[brief]

## Fix
[what changed and why]

## Testing
- [ ] Regression test added
- [ ] Security edge cases verified
EOF
)"

Otherwise: push branch, leave PR for later or skip entirely.

8. Update CHANGELOG

Add to [Unreleased] section:

- fix: <description> (#N if applicable)

9. Smoke Tests + Review

Always close with a short manual smoke test checklist (3–5 items). Infer the interface type:

• REST endpoint → curl commands covering happy path + error path
• Frontend → numbered browser steps (open URL → action → verify state)
• CLI → shell commands including --help and one error case
• Library → one-liner python -c "..." or inline snippet

Then suggest (in order, don't skip the first):

→ /review changes  ← always before /pre-commit
→ /pre-commit (only if --pr flag or user explicitly asks)

Do NOT jump straight to /pre-commit — /review changes should always come first.

Tech Debt Remediation

/fix is also the right skill for tech debt when:

• Change is isolated (no interface changes, no API breakage)
• Requires updating existing tests, not writing new suites
• Impact is contained to 1-3 files

For larger tech debt (cross-cutting, interface changes, architectural rework), use /implementation. Tracking: GitHub milestone TECH-DEBT.

Tips

• Keep fixes minimal — resist refactoring unrelated code
• Always document root cause in commit message or PR body for future reference