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tdd

Drive a single behavior change with Kent Beck's red → green → refactor loop — write the failing test FIRST, confirm it fails for the right reason, implement…

Skill by jhlee0409

IndexedMIT★ 2
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Works with Claude Code, Claude apps, Codex, Cursor, Gemini CLI, GitHub Copilot, VS Code, OpenCode, Goose, Windsurf. Read the repository before you give any tool access to your data.

npx agentmarket install skill/jhlee0409-tdd

Asks which of your tools to add it to (Claude Code, Codex, Cursor, VS Code, Windsurf, Gemini CLI, Claude Desktop) and shows the change first. See https://agentmart.dev/cli.

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About

Drive a single behavior change with Kent Beck's red → green → refactor loop — write the failing test FIRST, confirm it fails for the right reason, implement the minimum to pass, then refactor. Use when building a feature or fixing a bug test-first, or when the user says "TDD", "red-green-refactor", "테스트 먼저", "실패 테스트부터". For a hands-off loop that owns the whole cycle, delegate to the `tdd-runner` agent instead.

Use cases: testing, writing, agent-building

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Permissions

What this skill can do and what it asks for, from its SKILL.md. Checked Oct 25, 2026.

Tools
No tools found
Secrets
None asked for
Install scripts
None found

Network hosts it talks to 1

  • codeload.github.com · found in install command

Files it touches

  • ~/.claude/skills/tdd

Tools it pre-approves 6

From allowed-tools in SKILL.md: the agent may use these without asking you each time.

  • Read,
  • Grep,
  • Glob,
  • Bash,
  • Edit,
  • Write

What's inside

Skill name
tdd
Description
Drive a single behavior change with Kent Beck's red → green → refactor loop — write the failing test FIRST, confirm it fails for the right reason, implement the minimum to pass, then refactor. Use when building a feature or fixing a bug test-first, or when the user says "TDD", "red-green-refactor", "테스트 먼저", "실패 테스트부터". For a hands-off loop that owns the whole cycle, delegate to the `tdd-runner` agent instead.
License
MIT
Allowed tools
Read,, Grep,, Glob,, Bash,, Edit,, Write
Instructions
23 lines in SKILL.md · view on GitHub

Before installing

  • Pre-approves some shell commands

Files (1)

  • SKILL.md

SKILL.md (first lines)

# tdd

One behavior at a time. Never write implementation before a failing test for it.

## The loop
1. **🔴 Red** — write the smallest test that expresses the next behavior. Run it
   with the repo's runner (the `verify_command` / test command from
   `.claude/harness-kit.json`). Confirm it FAILS, and fails for the RIGHT reason
   (asserting the missing behavior — not a typo / import error). A test that
   passes immediately, or fails for the wrong reason, tells you nothing.
2. **🟢 Green** — write the MINIMUM implementation to make it pass. No extra
   features, no speculative generality. Run the test; confirm green.
3. **🔵 Refactor** — with the test green, clean up (names, duplication, shape)
   without changing behavior. Re-run; stay green.

## Discipline
- **Structural and behavioral changes never mix in one commit** (Tidy First).
- Keep the red→green step small — minutes, not an hour. If it's big, the test is
  too coarse; split it.
- A real run is the evidence: show the runner output (red, then green), not a claim.
- Mandatory for library / backend / CLI code, where there's no UI to eyeball.

From jhlee0409/omni-harness-kit, MIT.

More from jhlee0409/omni-harness-kit

Signals

Stars
2
Forks
1
Open issues
0
Last commit (this folder)
Jun 26, 2026 (4 months ago)
Last release
Jul 22, 2026 (3 months ago)

From GitHub (fetched Oct 24, 2026).

Details

License
MIT
Repository
github.com/jhlee0409/omni-harness-kit
First seen
Oct 24, 2026
Last checked
Oct 24, 2026
Source
GitHubgithub-graphql

More from jhlee0409

Cite this page

tdd skill. Agent Mart. https://agentmart.dev/skills/jhlee0409-tdd (last updated 2026-10-24)