A TDD-based workflow for fixing bugs and implementing features, mandating that a failing test is written before code changes.
Install
mkdir -p .claude/skills/fix-jvm-skills && curl -L -o skill.zip "https://agentskills.codes/api/skills/download/11872" && unzip -o skill.zip -d .claude/skills/fix-jvm-skills && rm skill.zipInstalls to .claude/skills/fix-jvm-skills
Activation
This is the description your AI agent reads to decide when to run this skill — the better it matches your request, the more reliably it fires.
Fix a bug or missing feature using TDD — write failing test first, then fix, refactor, verify, beautify. Use when a bug is discovered or a feature doesn't work as expected.Key capabilities
- →Understand and classify bugs or missing features
- →Write failing tests to reproduce issues
- →Implement minimum code to make tests pass
- →Refactor code for quality and efficiency
- →Verify fixes through screenshots or browser automation
How it works
The skill guides the user through a Test-Driven Development (TDD) process, starting with writing a failing test, then implementing the fix, refactoring, and verifying the changes.
Inputs & outputs
When to use fix
- →Fix a known bug
- →Implement a missing feature
- →Add test coverage for broken paths
- →Refactor code with TDD verification
About this skill
Fix with TDD
Fix a bug or missing feature by writing a failing test first, then making it pass.
Process
1. Understand
Describe the bug or missing behavior. Explore the codebase to find the relevant code paths.
- If UI-related: screenshot the current broken state (if browser automation is available)
- Find the relevant service, controller, and template/view files
- Check if there's an existing test class for this area
2. Classify — pick test approach
| Scenario | Test approach |
|---|---|
| Service/repository logic, DB queries | Integration tests with real DB |
| File uploads, external storage | Integration tests with mocks/stubs |
| Browser-visible UI, full user flows | End-to-end browser tests |
3. Red — write a failing test
⛔ MANDATORY GATE — do NOT write any fix code until this step is complete.
Write a test that reproduces the bug or asserts the missing behavior. Add to an existing test class if one covers this area, otherwise create a new one.
Run /test *FilterPattern and paste the failure output to confirm the test fails for the right reason.
4. Green — make the test pass
Write the minimum code to make the test pass.
- Compile the code
- Run the test — paste the green output to confirm pass
5. Refactor
Run /simplify to review changed code for reuse, quality, and efficiency. Then clean up anything remaining: remove duplication, extract methods if needed, ensure naming is consistent with surrounding code.
Run the test again — confirm still green after refactoring.
6. Verify
- UI fixes:
/restart-spring-boot→ verify the fix (screenshot or browser automation) → compare with the broken state from step 1 - Backend fixes: test output is sufficient proof
7. Beautify (UI fixes only)
If the fix introduced new UI elements:
design skill → refine → verify the UI
8. Commit
/commit
When not to use it
- →When a failing test cannot be written
- →When the fix does not require TDD principles
- →When the user wants to skip the mandatory failing test step
Limitations
- →A failing test must be written before any fix code.
- →Skipping the test writing step requires explicit user approval.
- →UI fixes require manual verification via screenshot or browser automation.
How it compares
This skill enforces a TDD workflow, ensuring that a failing test is written before any fix, which provides a verifiable and structured approach to bug fixing compared to direct code changes.
Compared to similar skills
fix side by side with the closest alternatives in the catalog.
| Skill | Installs | Updated | Safety | Difficulty |
|---|---|---|---|---|
| fix (this skill) | 0 | 4mo | No flags | Intermediate |
| reproduce-reduce-regress | 1 | 7mo | No flags | Intermediate |
| fix-file | 0 | 25d | No flags | Intermediate |
| python-testing-patterns | 77 | 2mo | Review | Intermediate |
Try saying
Example prompts that trigger this skill in your AI assistant.
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