/bug-fix

name: bug-fix
description: "Bug fix workflow. Use when: fixing bugs, resolving issues, regression fixes. Not for: new features (use feature-dev), understanding code (use code-explore). Output: fix + regression test + review gate."
allowed-tools: Read, Grep, Glob, Edit, Write, Bash

Bug Fix Skill

Trigger

• Keywords: bug, issue, fix, error, broken, failing

When NOT to Use

• New feature development (use feature-dev)
• Just want to understand code (use code-explore)
• Pure test-only tasks without feature changes (use `/codex-test-review` directly)

Prohibited Actions

❌ git add | git commit | git push — per @rules/git-workflow.md

This skill fixes bugs but does **not** commit. `/precommit` is a quality gate only. To commit, the user must invoke `/smart-commit --execute` separately.

Workflow

Investigate → Locate → Fix → Test + Review → Precommit Gate
  │             │       │         │                │
  ▼             ▼       ▼         ▼                ▼
gh issue      Grep    Edit     /verify          /precommit
/git-investigate  Read  tests  /codex-test-review
                               /codex-review-fast

Phase 1: Investigation

Before fixing: if the bug maps to a feature under `docs/features/`, read `docs/features/<key>/intent-<key>.md` when it exists — a fix that contradicts one of its `INV-*` invariants or Non-goals stops and asks the user (cite the line). No identifiable feature → nothing to load; proceed.

| Source | Action | |--------|--------| | GitHub Issue | `gh issue view <number>` | | Error message | `Grep("error message")` | | Code history | `/git-investigate` |

**Output root cause analysis**:

• Problem location: `src/<module>/<file>:<line>`
• Root cause: <specific cause>
• Impact scope: <which features are affected>

Phase 2: Fix

| Principle | Description | |-----------|-------------| | Minimal changes | Only modify what is necessary | | No new issues | Confirm changes don't affect other features | | Design preserved | Choose the smallest root-cause fix that keeps current responsibilities. If the fix moves a boundary or adds an abstraction, say which shape you chose and why — "direct fix; existing design retained" is the expected common answer |

Phase 3: Add Regression Test ⚠️

Follow `@rules/testing.md` for conventions (AAA, naming, evidence model). Follow `@rules/testing-project.md` for project-specific overrides.

**Bug fixes must have tests at the corresponding level:**

| Bug Type | Required | Recommended | |----------|----------|-------------| | Logic error | Unit | - | | Service issue | Unit | Integration | | API issue | Integration | E2E | | Cross-service/data flow | Integration | E2E | | User flow | E2E | - |

Phase 4: Verify + Review

Step 1: Run tests

/verify → all tests pass?
  Yes → Step 2
  No → fix failures → re-run /verify

Step 2: Test adequacy review (mandatory for code changes)

/codex-test-review → ✅ Tests sufficient?
  Yes → Step 3
  No → close gaps (Step 2a) → /codex-test-review --continue <threadId>

Step 2a: Gap closure

| Gap Type | Remediation | |----------|-------------| | Unit test missing | `/codex-test-gen` → write tests → `/verify` | | Integration/E2E missing | `/post-dev-test` → write tests → `/verify` |

Step 3: Code review (auto-loop)

/codex-review-fast → ✅ Ready?
  Yes → Precommit Gate
  No → fix issues → re-run /codex-review-fast (auto-loop)

Freshness rule

If code changes after the latest `✅ Tests sufficient` gate (e.g., fixes from code review), rerun `/verify` then `/codex-test-review --continue <threadId>` before proceeding to precommit gate.

Review Loop

**MUST re-review after fix until PASS** (per @rules/auto-loop.md)

Fix → Review → Issues found → Fix again → ... → ✅ Pass → Next step

Doc Sync

Doc Sync is governed by `@rules/auto-loop.md` (behavior-layer rule). After precommit pass, triggers conditionally when changes map to `docs/features/`.

Output

## Bug Fix Report
- **Root cause**: <analysis>
- **Fix**: <description of changes>
- **Regression test**: <test result>
- **Gate**: ✅ Fixed / ⛔ Needs further investigation

Verification Checklist

• [ ] Root cause identified and documented
• [ ] Regression test written at appropriate level
• [ ] All tests pass (`/verify`)
• [ ] Test adequacy reviewed (`/codex-test-review`)
• [ ] Code review passed (`/codex-review-fast` ✅ Ready)
• [ ] Precommit passed (`/precommit` ✅ All Pass)
• [ ] No `git add/commit/push` executed

Examples

Input: Fix issue #123 - calculation error
Action: gh issue view → locate → fix → write Unit Test → /verify → /codex-test-review → /codex-review-fast → /precommit

Input: API returning 500 error
Action: Grep error → read code → fix → write Integration Test → /verify → /codex-test-review → /codex-review-fast → /precommit