Bugfix

Bugfix

Fix robustness bugs one at a time using isolated worktrees, test-driven development, and parallel subagents.

Usage

/bugfix           # Pick the next unassigned robustness issue
/bugfix 786       # Fix a specific issue by number

Subagent context

All subagent prompts, scoring heuristics, and keyword maps live in .cursor/skills/bugfix/SUBAGENTS.md. Read that file before spawning any subagent, then pass only the relevant section as the prompt. Do NOT paste SUBAGENTS.md content into the main conversation context.

Workflow

Phase 1: Select and understand the bug

1. Check active worktrees first. Run git worktree list and report any existing pathfinder-fix-* worktrees so the user is aware of in-progress or stale fixes.

2. If no issue number provided, triage and prioritize:

   • Fetch open robustness issues: gh issue list --label robustness --state open --json number,title,labels,body
   • Read the Prioritization scoring section from SUBAGENTS.md and score each issue.
   • Present the top 3 candidates with scores. If the user says "just go", pick the highest.

3. Fetch the full issue body and comments:

   gh issue view <number>
   gh issue view <number> --comments
   

4. Check for scope mismatch. If the issue is also labeled enhancement, warn the user: "This issue includes new functionality beyond a pure bug fix. The bugfix skill targets minimal fixes — should I proceed with just the bug-fix portion, or hand off to a planning workflow for the full scope?"

5. Spawn two subagents in parallel. Read SUBAGENTS.md and use the Code investigation (Phase 1a) and Related issues (Phase 1b) prompt templates, filling in the issue details.

Phase 2: Classify the bug

6. Based on the Explore findings, classify the bug:

   Category	Example	Test track
   Logic bug	Wrong calculation, incorrect filtering, bad conditional	Unit test with Jest
   State bug	Race condition, stale state, incorrect lifecycle	Unit/integration test with Jest + RTL
   Rendering bug	Wrong component output, missing/duplicate elements	Component test with Jest + RTL
   UX behavior bug	Navigation broken, tab persistence lost, cross-component failure	Prefer RTL component test; E2E only if component test can't cover it
   Visual bug	Spinner off-axis, layout shift, styling regression	Structural test track (see below)

7. State a root cause hypothesis in one sentence. Present to the user for confirmation. Do NOT write tests until the root cause is agreed upon.

Structural test track (visual bugs)

Visual bugs often can't be captured with behavioral assertions, but they usually can be tested structurally. Instead of stopping to ask the user every time:

1. Check whether the bug can be expressed as a DOM structure or CSS class assertion (e.g., "spinner container should have display: flex and align-items: center", or "element should have class centered-spinner", or "only one .skip-button should exist in the section").
2. If a structural assertion is feasible, proceed with it as the failing test — no user gate needed.
3. If no structural assertion is possible (pure visual regression with no DOM/CSS signal), then flag to user with options: screenshot comparison E2E test, or fix-only with user approval.

Phase 3: Set up the worktree

8. Create an isolated worktree:

   git worktree add ../pathfinder-fix-<number> -b fix/<number>-<short-slug>
   

   Switch working directory to the worktree for all subsequent work.

9. Run npm install in the worktree.

Phase 4: Write failing tests FIRST

This is the most important phase. The test must prove the bug exists before any fix is attempted.

10. Spawn a Plan subagent. Read the Test design (Phase 4) prompt template from SUBAGENTS.md, fill in the confirmed root cause and Explore findings.

11. If test strategy calls for E2E (Playwright): check whether the dev server is running (curl -s http://localhost:3000/api/health). If not, tell the user: "This bug needs an E2E test but Grafana isn't running. Please start it with npm run server or I can write a component-level test instead." Prefer component-level RTL tests when they can adequately cover the behavior.

12. Write the test(s). Follow existing conventions:

    • Co-locate tests next to source files (foo.test.ts beside foo.ts)
    • Use src/test-utils/ for shared helpers
    • Import from @testing-library/react and @grafana/data/@grafana/ui as needed
    • Descriptive names: it('should not show double skip buttons when ...')
    • Test the boundary, not just the symptom

13. Run the tests and confirm they fail for the right reason:

    npx jest <test-file> --no-coverage
    

    If the test passes (bug not reproduced), reassess the root cause. Do NOT proceed until you have a failing test.

Phase 5: Commit the failing test

14. Commit the test separately:

    git add <test-files>
    git commit -m "test: add failing test for <short description>
    
    Demonstrates the bug described in #<number>. This test is
    expected to fail until the fix is applied in the next commit.
    
    Refs #<number>"
    

Phase 6: Fix the bug

15. Implement the minimal fix. Hard constraints:

    • Fix only the bug — no drive-by refactors
    • No new dependencies unless absolutely required
    • No changes to unrelated files
    • Respect architectural boundaries. The codebase enforces a tiered import graph via src/validation/architecture.test.ts. Your fix must NOT:
      • Introduce upward-tier imports (check TIER_MAP in src/validation/import-graph.ts)
      • Add lateral imports between Tier 2 engines unless unavoidable
      • Bypass engine barrel exports
      • Add entries to violation allowlists
    • If the fix requires crossing a boundary, stop and discuss with the user.

16. Run the failing test(s) and confirm they now pass:

    npx jest <test-file> --no-coverage
    

Phase 7: Verify no regressions

17. Run the full check suite:

    npm run check
    

    Fix any failures introduced by your change. If fixing would require out-of-scope changes, stop and tell the user.

Phase 8: Commit the fix

18. Commit the fix separately:

    git add <fix-files>
    git commit -m "fix: <description>
    
    Fixes #<number>"
    

Phase 9: Record pattern and report

19. Record the fix pattern. Append one entry to docs/developer/bugfix-patterns.md (create it if it doesn't exist):

    | #<number> | <category> | <root cause pattern — one phrase> | <files touched> | <date> |
    

    If the file is new, add this header first:

    # Bugfix patterns
    
    Patterns from resolved robustness issues. Loaded during `/bugfix` Phase 2 to inform classification and root cause hypotheses.
    
    | Issue | Category | Root cause pattern | Files | Date |
    | ----- | -------- | ------------------ | ----- | ---- |
    

20. Report to the user:

    • Bug: one sentence
    • Root cause: one sentence
    • Test: what the test proves
    • Fix: what the fix does
    • Related issues: sibling robustness issues that may share this root cause
    • Branch: fix/<number>-<slug> in worktree ../pathfinder-fix-<number>

21. Offer next steps:

    • push — push branch and create a PR
    • next — start the next highest-priority robustness issue
    • merge — rebase onto main and merge locally (check for conflicts with other fix branches first)
    • cleanup — remove this worktree (git worktree remove ../pathfinder-fix-<number>)
    • status — list all active fix worktrees and their branches

Hard constraints

1. NEVER skip the failing-test phase. If you cannot reproduce the bug in a test, stop and discuss with the user rather than fixing blindly.
2. NEVER modify existing test assertions to make them pass — write new tests or extend existing ones.
3. One bug per worktree. Each issue gets its own branch and worktree.
4. Minimal diff. Only tests and the fix. No formatting changes, no unrelated refactors.
5. Use subagents for exploration, not for writing code. All code changes happen in the main context.
6. Two-commit structure. Commit 1: failing test. Commit 2: the fix.
7. Confirm root cause before writing tests. Present hypothesis to user first.
8. Load prior patterns. In Phase 2, check if docs/developer/bugfix-patterns.md exists and read it. Use prior root cause patterns to inform the current hypothesis.

Subagent strategy