Superpowers Test Driven Development
christopherarter/superpowers-reasonix
Writing or fixing any code?. An agent skill from christopherarter/superpowers-reasonix.
AI DevKit · Test-driven development — write a failing test before writing production code.
Install TDD
$ npx skills add codeaholicguy/ai-devkit --skill tdd -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install codeaholicguy/ai-devkit tdd --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/codeaholicguy/ai-devkit.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/tdd .claude/skills/tdd && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "tdd" agent skill from https://github.com/codeaholicguy/ai-devkit/tree/main/skills/tdd into .claude/skills/tdd/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "tdd", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/codeaholicguy/ai-devkit/tree/main/skills/tddType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add codeaholicguy/ai-devkit --skill tdd -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install codeaholicguy/ai-devkit tdd --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/codeaholicguy/ai-devkit.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/tdd .agents/skills/tdd && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "tdd" agent skill from https://github.com/codeaholicguy/ai-devkit/tree/main/skills/tdd into .agents/skills/tdd/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "tdd", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add codeaholicguy/ai-devkit --skill tdd -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install codeaholicguy/ai-devkit tdd --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/codeaholicguy/ai-devkit.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/tdd .cursor/skills/tdd && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "tdd" agent skill from https://github.com/codeaholicguy/ai-devkit/tree/main/skills/tdd into .cursor/skills/tdd/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "tdd", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/codeaholicguy/ai-devkit.git --path skills/tdd--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add codeaholicguy/ai-devkit --skill tdd -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install codeaholicguy/ai-devkit tdd --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/codeaholicguy/ai-devkit.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/tdd .gemini/skills/tdd && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "tdd" agent skill from https://github.com/codeaholicguy/ai-devkit/tree/main/skills/tdd into .gemini/skills/tdd/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "tdd", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install codeaholicguy/ai-devkit tddInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add codeaholicguy/ai-devkit --skill tdd -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/codeaholicguy/ai-devkit.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/tdd .github/skills/tdd && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "tdd" agent skill from https://github.com/codeaholicguy/ai-devkit/tree/main/skills/tdd into .github/skills/tdd/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "tdd", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add codeaholicguy/ai-devkit --skill tdd -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install codeaholicguy/ai-devkit tdd --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/codeaholicguy/ai-devkit.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/tdd .opencode/skills/tdd && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "tdd" agent skill from https://github.com/codeaholicguy/ai-devkit/tree/main/skills/tdd into .opencode/skills/tdd/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "tdd", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
tdd- GitHub stars
- 1.6k
- Token cost
- ~838 tokens
- SKILL.md length
- 476 words
- Files
- 2
- Skills in repo
- 28
- Repo updated
- First seen
- Licence
- Apache-2.0
At a glance
AI DevKit · Test-driven development — write a failing test before writing production code.
- Works in 3 steps: Red — Write a test for the next… → Green — Write the minimum production… → Refactor — Clean up both test and…
- Implementing new functionality
- SKILL.md covers Hard Rules, Cycle, Rules for Each Step and Anti-Patterns, plus 2 more sections
- Calls npx
What it does
TDD is an agent skill from codeaholicguy/ai-devkit. AI DevKit · Test-driven development — write a failing test before writing production code. Use when implementing new functionality, adding behavior, or fixing bugs during active development.
Its SKILL.md is about 840 tokens, which your agent loads only when the skill is triggered. The skill folder holds 2 other files (for example `agents/openai.yaml`).
It sits in Testing & QA, covering Test-driven development and Failing and flaky tests. The repository describes itself as: The control plane for AI coding agents. The licence is Apache-2.0.
When your agent uses it
- Implementing new functionality
- Adding behavior
- Fixing bugs during active development
Example prompts
- “/tdd”
Requirements
- Node.js
Workflow steps
3 steps, taken from the first numbered list in SKILL.md.
- Red — Write a test for the next behavior. Run it. It must fail. Read the failure message — it should describe the missing behavior.
- Green — Write the minimum production code to make the test pass. Nothing more. Run the test. Apply the verify skill.
- Refactor — Clean up both test and production code. Run the test again. Still green? Done. Apply the verify skill.
What it can do on your machine
Read from SKILL.md and the folder at commit 7ef0cd5. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
Shell commands in SKILL.md call:
npx
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md. Its commands use npx, which can reach the network depending on how they are called.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
TDD loads about 838 tokens when it runs. Until then it costs about 49 tokens; SKILL.md has 476 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from codeaholicguy/ai-devkit at commit 7ef0cd5, republished under its Apache-2.0 licence (© codeaholicguy). 476 words, ~838 tokens.
Download SKILL.mdSave it as
.claude/skills/tdd/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.- name
- tdd
- description
- AI DevKit · Test-driven development — write a failing test before writing production code. Use when implementing new functionality, adding behavior, or fixing bugs during active development.
TDD
Red. Green. Refactor. In that order, every time.
Hard Rules
- No production code without a failing test first.
- If production code was written before its test, delete it and start over with a failing test.
- Never skip the red step. A test that has never failed proves nothing.
Cycle
For each unit of behavior:
- Red — Write a test for the next behavior. Run it. It must fail. Read the failure message — it should describe the missing behavior.
- Green — Write the minimum production code to make the test pass. Nothing more. Run the test. Apply the
verifyskill. - Refactor — Clean up both test and production code. Run the test again. Still green? Done. Apply the
verifyskill.
Then pick the next behavior and repeat.
Rules for Each Step
Red:
- Test one behavior, not one function. Name the test after what the system should do, not what the function is called.
- The test must fail for the right reason — a missing method, wrong return value, unmet condition. Not a syntax error or import failure.
- If the test passes immediately, it's not testing new behavior. Delete it or pick a different behavior.
Green:
- Write the simplest code that passes. Hardcode if needed — the next test will force generalization.
- Do not add code "while you're in there." If it's not required by a failing test, it doesn't exist yet.
- Do not refactor during green. Pass first, clean second.
Refactor:
- Remove duplication between test and production code.
- Extract only when you see real duplication, not predicted duplication.
- Tests must still pass after every refactor move. Run them after each change.
Show full SKILL.md (207 more words)Show less
Anti-Patterns
| Pattern | Problem | Fix |
|---|---|---|
| Test-after | Code shapes the test instead of the other way around | Delete the code, write the test first |
| Testing internals | Tests break on refactor, not on behavior change | Test public behavior only |
| Giant red step | Multiple behaviors in one test | One assertion per behavior |
| Gold-plating green | Adding code no test requires | Remove untested code |
| Skipping refactor | Tech debt accumulates immediately | Refactor before the next red |
| Mock-heavy tests | Tests pass but real code fails | Prefer real dependencies, mock at boundaries only |
Red Flags and Rationalizations
| Rationalization | Why It's Wrong | Do Instead |
|---|---|---|
| "This is too simple to test first" | Simple code still needs a spec | Write the test — it'll be fast |
| "I'll add the test right after" | You won't, and the code will shape the test | Test first, always |
| "I need to see the design first" | The test IS the design | Let the test drive the interface |
| "Mocking is too hard for this" | Difficulty mocking signals tight coupling | Fix the design, then test |
| "The test would be identical to the implementation" | Then you're testing internals | Test the behavior from the outside |
Memory Integration
After completing a TDD session, store reusable test patterns (setup, assertions, fixtures): npx ai-devkit@latest memory store --title "<pattern>" --content "<details>" --tags "tdd,testing"
© codeaholicguy, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
SKILL.md and 1 other file in skills/tdd of codeaholicguy/ai-devkit.
- SKILL.md
- agents/openai.yaml
Open the folder on GitHubat commit 7ef0cd5
Compare with similar skills
TDD next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| TDD this skillcodeaholicguy/ai-devkit | 1.6k | — | ~838 | Automated safety check: Pass | Apache-2.0 | |
| Superpowers Test Driven Developmentchristopherarter/superpowers-reasonix | 102 | — | ~1.9k | Automated safety check: Pass | MIT | |
| Openspec Plus TDDelastic/terraform-provider-elasticstack | 210 | 1 repos | ~4.7k | Automated safety check: Pass | Apache-2.0 | |
| Fix BugMelbourneDeveloper/dart_node | 113 | 1 repos | ~709 | Automated safety check: Notes | None | |
| Evanflow Debugevanklem/evanflow | 418 | — | ~760 | Automated safety check: Pass | Custom licence | |
| TDD Workflows TDD Greenaiskillstore/marketplace | 430 | 7 repos | ~568 | Automated safety check: Pass | None |
Similar skills
- Official
Openspec Plus TDD
elastic/terraform-provider-elasticstack
MANDATORY skill that activates whenever code is written to implement an OpenSpec change task.
Fix Bug
MelbourneDeveloper/dart_node
Fix a bug using test-driven development. An agent skill from MelbourneDeveloper/dart_node.
Evanflow Debug
evanklem/evanflow
Root-cause discipline for bugs, test failures, and unexpected behavior.
TDD Workflows TDD Green
aiskillstore/marketplace
Implement the minimal code needed to make failing tests pass in the TDD green phase.
Test First Changes
pdparchitect/noodle
Test-first procedure for every behaviour change in Noodle. An agent skill from pdparchitect/noodle.
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Related
Categories
Questions about TDD
What does TDD do?
AI DevKit · Test-driven development — write a failing test before writing production code. TDD is an agent skill from codeaholicguy/ai-devkit. AI DevKit · Test-driven development — write a failing test before writing production code.
When should I use TDD?
TDD fits situations like: implementing new functionality; adding behavior; fixing bugs during active development.
How do I install TDD in Claude Code?
Run `npx skills add codeaholicguy/ai-devkit --skill tdd -a claude-code`. Or copy the skill folder (skills/tdd in codeaholicguy/ai-devkit) into .claude/skills/tdd in your project. Claude Code loads it when a task matches its description.
How do I install TDD in Codex?
Run `npx skills add codeaholicguy/ai-devkit --skill tdd -a codex`. Or copy the skill folder (skills/tdd in codeaholicguy/ai-devkit) into .agents/skills/tdd in your project. Codex loads it when a task matches its description.
Can I use TDD in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add codeaholicguy/ai-devkit --skill tdd -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/tdd, .gemini/skills/tdd, .github/skills/tdd and .opencode/skills/tdd in your project.
What does TDD need to run?
Going by SKILL.md and its folder, TDD needs the command-line tools its instructions call (npx). Our summary lists: Node.js.
Does TDD access the network?
SKILL.md contains no URLs. Its commands use npx, which can reach the network depending on how they are called. This is read from the text; nothing was executed.
Is TDD safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does TDD use?
TDD is published under the Apache-2.0 licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does TDD use?
About 838 tokens (SKILL.md is roughly 3.4k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to TDD?
Skills that share tags, products or a category with TDD: Superpowers Test Driven Development (christopherarter/superpowers-reasonix, 102 stars), Openspec Plus TDD (elastic/terraform-provider-elasticstack, 210 stars), Fix Bug (MelbourneDeveloper/dart_node, 113 stars) and Evanflow Debug (evanklem/evanflow, 418 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains TDD?
codeaholicguy (a GitHub user) maintains it in codeaholicguy/ai-devkit, which has 1,642 GitHub stars. The repository holds 28 skills in this directory. The repository was last updated on October 7, 2026.
Source: codeaholicguy/ai-devkit on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.