tdd skill
Drive a change through a red-green-refactor loop - failing test first, minimal code to pass, then clean up. Use when implementing a feature or fixing a bug where correctness matters and a test can pin the behavior. Says "TDD", "test first", "red green refactor", "write the test first".
Is the tdd skill safe?
Clean: nothing in its files matched our rules. We read 1 file in the folder on 2026-09-28.
No findings.
Install the tdd skill
A skill is a folder. Copy it into your agent's skills folder and the agent loads it when the task matches its description.
git clone --depth 1 https://github.com/rohitg00/pro-workflow.git /tmp/pro-workflow mkdir -p ~/.claude/skills cp -r /tmp/pro-workflow/skills/tdd ~/.claude/skills/tdd
In the Claude apps, zip the folder and upload it from the Skills settings. The folder on GitHub
The instructions your agent would load
SKILL.md as published, without the frontmatter. Read it on GitHub
tdd
The agent codes better with a tight feedback loop than with a long specification. A failing test is the tightest loop there is: it states the target, and the target either goes green or it does not.
The loop
Run it. Confirm it fails for the right reason - a test that passes before you write the code is testing nothing. If it errors instead of failing on the assertion, fix the test setup first.
- Red. Write one failing test that states the next slice of behavior.
solution, not the abstraction - the minimal move. Run the test. Green.
- Green. Write the least code that makes the test pass. Not the general
name things, simplify. Re-run after every edit. Behavior is frozen; only the shape changes.
- Refactor. Now clean up with the test as a net: remove duplication,
speed limit - never take on a step too big to hold a single test.
- Repeat for the next slice. Small slices. The rate of feedback is the
What makes a test worth writing
not on which private method got called. A test that breaks on every refactor is a liability.
- Tests behavior, not implementation. Assert on the observable result,
should know what broke without reading the body.
- One reason to fail. Each test pins one behavior. When it goes red you
filesystem), not internal collaborators. A test that mocks the thing under test asserts nothing.
- Real seams, minimal mocks. Mock at the system boundary (network, clock,
after setting x) verifies nothing. Assert the value the behavior should produce.
- No tautologies. A test that restates the implementation (expect(x).toBe(x)
When to reach for it
Reach for TDD when the behavior is specifiable and a test can pin it: business logic, parsers, state machines, bug fixes (write the failing case first, then fix). Skip it for pure exploration, throwaway spikes, and layout-only UI where a test asserts nothing a human would not eyeball.
Output contract
Show each red-green transition, not just the final green. If a test is hard to write, say what the difficulty reveals about the design - untestable code is usually badly-seamed code, and that is a finding, not an obstacle.
More skills from rohitg00/pro-workflow
- Aagent-teamsCoordinate multiple Claude Code sessions as a team — lead + teammates with shared task lists, mailbox messaging, and file-lock claiming. Patterns for team sizing, task decomposition, and when to use teams vs sub-agents vs worktrees.
- Aauto-setupAuto-configure quality gates, hooks, and settings for a new project. Detects project type and sets up appropriate tooling. Use when onboarding a new codebase.
- Abatch-orchestrationDecompose large-scale changes into independent units and spawn parallel agents in isolated worktrees. Use for migrations, refactors, codemods, and any change touching 10+ files with the same pattern.
- Cbug-captureCapture a user-reported defect as a durable GitHub issue written in the project's own domain language. Explores the codebase in parallel for context but never leaks file paths or line numbers into the issue. Use when the user reports a bug conversationally, runs a QA pass, or says "file an issue", "log this as a bug", "capture this".
- Acompact-guardSmart context compaction with state preservation. Saves critical files, task progress, and working state before compaction, restores after. Use before manual compact or when auto-compact triggers.
- Acontext-engineeringMaster the four operations of context engineering — Write, Select, Compress, Isolate. Manage token budgets, compaction strategies, and context partitioning to keep AI sessions sharp and efficient.
- Acontext-optimizerOptimize token usage and context management. Use when sessions feel slow, context is degraded, or you're running out of budget.
- Acost-trackerTrack session costs, set budget alerts, and optimize token spend. Use to check costs mid-session or set spending limits.
- Adesign-engineeringApply interface craft when building or reviewing UI - motion, easing, timing, springs, component feel, and visual foundations. Use when building a component, animation, transition, hover or press state, modal, drawer, toast, or when polishing an interface so it feels right. Says "make this feel better", "add an animation", "polish the UI", "review this component".
- AdeslopRemove AI-generated code slop, unnecessary comments, and over-engineering from the current branch diff. Cleans up boilerplate, simplifies abstractions, strips defensive code, and in skill-file mode lints SKILL.md files for quality. Use when cleaning up code, simplifying, removing boilerplate, before committing, or when reviewing a skill before promoting it.
- Adomain-modelingBuild the project's shared language and bounded contexts before writing code, so names stay consistent and the agent stops paraphrasing domain concepts. Produces a CONTEXT.md glossary and decision records. Use at the start of a project or feature, or when the codebase and the people describing it speak different languages.
- Afile-watcherConfigure file watching hooks to auto-react to config changes, env file updates, and dependency modifications. Use to set up reactive workflows.