tdd
Write code through a disciplined, BDD-framed Test-Driven Development loop: build a behavior test list, then drive each behavior through red-green-refactor with an enforced observed-failure gate. Use when the user wants to implement, build, or write code test-first, "do TDD", follow "red-green-refactor", drive code from tests, choose the next test by the Transformation Priority Premise (TPP) or ZOMBIES ordering, or grow a feature behavior-by-behavior with tests leading. This skill writes and changes code; it does not produce a test plan document (use automated-test-planning, or manual-test-plan
npx skills add testdouble/han --skill tdd --agent claude-code
Same command for any agent — swap --agent for codex, cursor, copilot.
Weekly change comes from our own snapshots, not the repository page — it measures attention, not adoption.
## Project Context - git installed: !`which git 2>/dev/null || echo "not installed"` - current branch: !`git branch --show-current 2>/dev/null || echo unknown` - CLAUDE.md: !`find . -maxdepth 1 -name "CLAUDE.md" -type f` - project-discovery.md: !`find . -maxdepth 3 -name "project-discovery.md" -type f` - personal config directory: !`echo "${CLAUDE_CONFIG_DIR:-$HOME/.claude}"` - project .han/config.md: !`cat .han/config.md 2>/dev/null || echo ""` As your first action, use the Read tool on `.han/config.md` inside the `personal config directory` path above. A read that returns no file is no personal configuration: continue silently. When that file or the `project .han/config.md` probe supplies content, apply it per [config-rule.md](../../references/config-rule.md), which governs precedence between the two files, relative-path resolution, and what to do with a file that reads but cannot be used. ## Constraints (read before anything else) This skill writes production and test code in your working tree. It is an execution skill, not a document generator. These constraints shape every step and override any instinct to move faster. - **The observed-failure gate is load-bearing.** No produc
- Project Context
- Constraints (read before anything else)
- Step 1: Resolve Project Config and Confirm Scope
- Step 2: Build the BDD Test List
- Step 3: The Red-Green-Refactor Loop
- Red
- Green
- Refactor (non-skippable)
- Close the cycle
- Step 4: Close the Outer Loop
- Step 5: Final Verification and Summary
What does the tdd skill do?
Write code through a disciplined, BDD-framed Test-Driven Development loop: build a behavior test list, then drive each behavior through red-green-refactor with an enforced observed-failure gate. Use when the user wants to implement, build, or write code test-first, "do TDD", follow "red-green-refactor", drive code from tests, choose the next test by the Transformation Priority Premise (TPP) or ZOMBIES ordering, or grow a feature behavior-by-behavior with tests leading. This skill writes and changes code; it does not produce a test plan document (use automated-test-planning, or manual-test-plan
How do I install it?
Run `npx skills add testdouble/han --skill tdd --agent claude-code` — it drops the skill into your project so the agent can pick it up. Swap the --agent value for codex, cursor or copilot if you use one of those.
Where does this skill come from?
From testdouble/han, a repository with 154 stars. We read it straight from the repository tree rather than a submitted listing, so what you see here is what is actually published.
Is a popular skill a good skill?
Not necessarily. Stars measure attention, not adoption — a repository can trend for a week and be abandoned. That is why we show the weekly change from our own snapshots next to the total, instead of a single flattering number.