fix - SKILL.md Agent Skill

name: fix description: Fix a GitHub issue end-to-end — fetches issue, creates worktree, plans and implements fix, runs validation, opens PR, cleans up. argument-hint: [issue-number-or-url] disable-model-invocation: true allowed-tools: Bash, Read, Write, Edit, Glob, Grep, WebFetch, WebSearch

Fix GitHub Issue

You are fixing a GitHub issue for the exercism/website repository.

Issue details

!`gh issue view $(echo "$ARGUMENTS" | grep -oE '[0-9]+$') --json number,title,body,labels,comments`

Issue number: !echo "$ARGUMENTS" | grep -oE '[0-9]+$'

Critical: Two phase.

Your work is split into two phases.

The first phase is purely planning. You must NOT make any changes to git state (switching branches, creating branches, creating worktrees, etc). You should presume that other work is SIMULTANEOUSLY happening WHILE you are planning.

Once the plan has been APPROVED by the user you should check the current git state:

Run git status to check for uncommitted changes.
If there are uncommitted or staged changes, STOP and ask the user how to proceed. Do NOT stash or discard anything.

Never destroy or discard existing work.

If the plan has been approved and the working tree is clean, continue with your work.

Workflow

Follow these steps in order. Do not skip any step.

Step 1: Understand the issue

Read the issue details above carefully. Identify:

What is broken or needs to change
Which parts of the codebase are likely affected
Any reproduction steps or error messages mentioned

Read the relevant docs/context/ files for the area of the codebase involved.

Step 2: Plan the fix

Do NOT create a branch or worktree yet. Stay on the current branch while planning.

Use /plan to enter plan mode. Explore the codebase thoroughly:

Find the relevant files using Glob and Grep
Read the code to understand current behavior
Identify what needs to change and why
Check for existing test coverage
Look at similar patterns in the codebase for reference

Design a complete fix before writing any code.

Step 3: Create a worktree

Only create the worktree after the plan is approved. The issue number has been extracted above (works whether the argument was a full URL like https://github.com/exercism/website/issues/8370 or just 8370).

git pull --ff-only origin main
mkdir -p worktrees
git worktree add worktrees/fix-<issue-number> -b fix/<issue-number>
cd worktrees/fix-<issue-number>

After creating the worktree, symlink node_modules and husky from the main repo so that JS tooling (prettier, eslint, jest) and pre-commit hooks work without a full yarn install:

ln -s /Users/iHiD/Code/exercism/website/node_modules node_modules
ln -s /Users/iHiD/Code/exercism/website/.husky/_ .husky/_

CRITICAL: You MUST cd into the worktree immediately after creating it. All subsequent work — file reads, edits, bash commands, tests — MUST happen from inside the worktree directory using cd worktrees/fix-<issue-number> && <command> on every Bash call. Do NOT use absolute paths to the worktree from the main repo. The main repo stays untouched on its current branch.

Step 4: Implement the fix

After the plan is approved and the worktree is created, implement the changes:

Follow existing patterns and conventions in the codebase
Business logic belongs in /app/commands/ using the Mandate pattern
Keep controllers thin — delegate to commands
Add or update tests as appropriate (Minitest, FactoryBot)
Keep changes minimal and focused on the issue

Step 5: Run tests

Run the relevant tests for the changes you made:

bundle exec rails test <test-file-or-directory>

If you made front-end changes, also run yarn test before committing.

Rubocop and brakeman will be checked automatically by the pre-commit hook when you commit — you do not need to run them manually.

Step 6: Commit the changes

Stage only the files you changed (do not use git add -A or git add .). Write a clear commit message that describes the fix.

Step 7: Push and create a PR

Push the branch and create a pull request:

git push -u origin fix/<issue-number>

Create the PR using gh pr create. The PR body must include Closes #<issue-number> to auto-close the issue on merge:

gh pr create --title "<concise title>" --body "$(cat <<'EOF'
Closes #<issue-number>

## Summary
<bullet points describing what changed and why>

## Test plan
<checklist of how the fix was validated>

🤖 Generated with [Claude Code](https://claude.com/claude-code)
EOF
)"

Step 8: Clean up worktree

cd /Users/iHiD/Code/exercism/website
git worktree remove worktrees/fix-<issue-number>

This removes the worktree directory. The branch remains on the remote for the PR.

Report the PR URL to the user.