Agent skill

TDD

Test-Driven Development methodology and red-green-refactor workflow (formerly test-tdd).

MITAuto-check passedTesting & QA

Install TDD

skills CLI

$ npx skills add pproenca/dot-skills --skill tdd -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install pproenca/dot-skills tdd --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/pproenca/dot-skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/.curated/tdd .claude/skills/tdd && rm -rf skills-src

Use ~/.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/

Paste into Claude Code

Install the "tdd" agent skill from https://github.com/pproenca/dot-skills/tree/master/skills/.curated/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

$skill-installer install https://github.com/pproenca/dot-skills/tree/master/skills/.curated/tdd

Type 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.

skills CLI

$ npx skills add pproenca/dot-skills --skill tdd -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install pproenca/dot-skills tdd --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/pproenca/dot-skills.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/.curated/tdd .agents/skills/tdd && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "tdd" agent skill from https://github.com/pproenca/dot-skills/tree/master/skills/.curated/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.

skills CLI

$ npx skills add pproenca/dot-skills --skill tdd -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install pproenca/dot-skills tdd --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/pproenca/dot-skills.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/.curated/tdd .cursor/skills/tdd && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "tdd" agent skill from https://github.com/pproenca/dot-skills/tree/master/skills/.curated/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

$ gemini skills install https://github.com/pproenca/dot-skills.git --path skills/.curated/tdd

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add pproenca/dot-skills --skill tdd -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install pproenca/dot-skills tdd --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/pproenca/dot-skills.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/.curated/tdd .gemini/skills/tdd && rm -rf skills-src

Use ~/.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/

Paste into Gemini CLI

Install the "tdd" agent skill from https://github.com/pproenca/dot-skills/tree/master/skills/.curated/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.

GitHub CLI

$ gh skill install pproenca/dot-skills tdd

Installs 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).

skills CLI

$ npx skills add pproenca/dot-skills --skill tdd -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/pproenca/dot-skills.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/.curated/tdd .github/skills/tdd && rm -rf skills-src

Use ~/.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/

Paste into GitHub Copilot

Install the "tdd" agent skill from https://github.com/pproenca/dot-skills/tree/master/skills/.curated/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.

skills CLI

$ npx skills add pproenca/dot-skills --skill tdd -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install pproenca/dot-skills tdd --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/pproenca/dot-skills.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/.curated/tdd .opencode/skills/tdd && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "tdd" agent skill from https://github.com/pproenca/dot-skills/tree/master/skills/.curated/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: 214
Token cost: ~1.4k tokens
SKILL.md length: 513 words
Files: 48 (incl. references, assets)
Skills in repo: 182
Repo updated: Aug 15, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

Test-Driven Development methodology and red-green-refactor workflow (formerly test-tdd).

Works in 8 steps: Red-Green-Refactor Cycle (CRITICAL) → Test Design Principles (CRITICAL) → Test Isolation & Dependencies (HIGH) → …
Write tests first
SKILL.md covers When to Apply, TDD Workflow, Rule Categories by Priority and Quick Reference, plus 3 more sections
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

TDD is an agent skill from pproenca/dot-skills. Test-Driven Development methodology and red-green-refactor workflow (formerly test-tdd). This skill should be used when practicing TDD, writing tests first, designing tests before implementation, or reviewing test-first approaches. Triggers on "write tests first", "test before code", "red green refactor", "test driven development". This skill does NOT cover Vitest framework specifics (use vitest skill) or API mocking with MSW (use msw skill).

Its SKILL.md is about 1.4k tokens, which your agent loads only when the skill is triggered. The skill folder holds 50 other files, including reference files and assets (for example `AGENTS.md`, `README.md` and `assets/templates/_template.md`).

It sits in Testing & QA, covering Test-driven development. It works with Vitest. The repository describes itself as: A collection of AI agent skills following the Agent Skills open format. The licence is MIT.

When your agent uses it

Write tests first
Test before code
Red green refactor
Test driven development

Example prompts

“write tests first”
“test before code”
“red green refactor”
“/tdd”

Workflow steps

8 steps, taken from the step headings in SKILL.md.

Red-Green-Refactor Cycle (CRITICAL)
Test Design Principles (CRITICAL)
Test Isolation & Dependencies (HIGH)
Test Data Management (HIGH)
Assertions & Verification (MEDIUM)
Test Organization & Structure (MEDIUM)
Test Performance & Reliability (MEDIUM)
Test Pyramid & Strategy (LOW)

What it can do on your machine

Read from SKILL.md and the folder at commit cf93c57. 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
No scripts in the folder and no shell commands in SKILL.md.
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
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 1.4k tokens when it runs, and up to ~24k if it reads all its reference files. Until then it costs about 113 tokens; SKILL.md has 513 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~113
When it runs · the whole SKILL.md, loaded when a task matches: ~1.4k
With references · SKILL.md plus every file in references/, read only if the agent opens them: ~24k

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 pproenca/dot-skills at commit cf93c57, republished under its MIT licence (© pproenca). 513 words, ~1,379 tokens.

Download SKILL.mdSave it as .claude/skills/tdd/SKILL.md (or your agent's skills folder). This skill also uses 47 other files; get the full folder from GitHub.

name: tdd
description: Test-Driven Development methodology and red-green-refactor workflow (formerly test-tdd). This skill should be used when practicing TDD, writing tests first, designing tests before implementation, or reviewing test-first approaches. Triggers on "write tests first", "test before code", "red green refactor", "test driven development". This skill does NOT cover Vitest framework specifics (use vitest skill) or API mocking with MSW (use msw skill).

Community Test-Driven Development Best Practices

Comprehensive guide to Test-Driven Development practices, designed for AI agents and LLMs. Contains 42 rules across 8 categories, prioritized by impact to guide test writing, refactoring, and code generation.

When to Apply

Reference these guidelines when:

Writing new tests using TDD workflow
Implementing the red-green-refactor cycle
Designing test structure and organization
Creating test data and fixtures
Reviewing or refactoring existing test suites

TDD Workflow

RED: Write a failing test that defines desired behavior
GREEN: Write minimal code to make the test pass
REFACTOR: Clean up code while keeping tests green
Repeat for each new behavior

Rule Categories by Priority

Priority	Category	Impact	Prefix
1	Red-Green-Refactor Cycle	CRITICAL	`cycle-`
2	Test Design Principles	CRITICAL	`design-`
3	Test Isolation & Dependencies	HIGH	`isolate-`
4	Test Data Management	HIGH	`data-`
5	Assertions & Verification	MEDIUM	`assert-`
6	Test Organization & Structure	MEDIUM	`org-`
7	Test Performance & Reliability	MEDIUM	`perf-`
8	Test Pyramid & Strategy	LOW	`strat-`

Quick Reference

1. Red-Green-Refactor Cycle (CRITICAL)

cycle-write-test-first - Write the Test Before the Implementation
cycle-minimal-code-to-pass - Write Only Enough Code to Pass the Test
cycle-refactor-after-green - Refactor Immediately After Green
cycle-verify-test-fails-first - Verify the Test Fails Before Writing Code
cycle-small-increments - Take Small Incremental Steps
cycle-maintain-test-list - Maintain a Test List

2. Test Design Principles (CRITICAL)

design-test-behavior-not-implementation - Test Behavior Not Implementation
design-one-assertion-per-test - One Logical Assertion Per Test
design-descriptive-test-names - Use Descriptive Test Names
design-aaa-pattern - Follow the Arrange-Act-Assert Pattern
design-test-edge-cases - Test Edge Cases and Boundaries
design-avoid-logic-in-tests - Avoid Logic in Tests

3. Test Isolation & Dependencies (HIGH)

isolate-mock-external-dependencies - Mock External Dependencies
isolate-no-shared-state - Avoid Shared Mutable State Between Tests
isolate-deterministic-tests - Write Deterministic Tests
isolate-prefer-stubs-over-mocks - Prefer Stubs Over Mocks for Queries
isolate-use-dependency-injection - Use Dependency Injection for Testability

4. Test Data Management (HIGH)

data-use-factories - Use Factories for Test Data Creation
data-minimal-setup - Keep Test Setup Minimal
data-avoid-mystery-guests - Avoid Mystery Guests
data-unique-identifiers - Use Unique Identifiers Per Test
data-builder-pattern - Use Builder Pattern for Complex Objects

Show full SKILL.md (206 more words)Show less

5. Assertions & Verification (MEDIUM)

assert-specific-assertions - Use Specific Assertions
assert-error-messages - Assert on Error Messages and Types
assert-no-assertions-antipattern - Every Test Must Have Assertions
assert-custom-matchers - Create Custom Matchers for Domain Assertions
assert-snapshot-testing - Use Snapshot Testing Judiciously

6. Test Organization & Structure (MEDIUM)

org-group-by-behavior - Group Tests by Behavior Not Method
org-file-structure - Follow Consistent Test File Structure
org-setup-teardown - Use Setup and Teardown Hooks Appropriately
org-test-utilities - Extract Reusable Test Utilities
org-parameterized-tests - Use Parameterized Tests for Variations

7. Test Performance & Reliability (MEDIUM)

perf-fast-unit-tests - Keep Unit Tests Under 100ms
perf-avoid-network-calls - Eliminate Network Calls in Unit Tests
perf-fix-flaky-tests - Fix Flaky Tests Immediately
perf-parallelize-tests - Parallelize Independent Tests
perf-avoid-sleep - Avoid Arbitrary Sleep Calls

8. Test Pyramid & Strategy (LOW)

strat-test-pyramid - Follow the Test Pyramid
strat-mutation-testing - Use Mutation Testing to Validate Test Quality
strat-coverage-targets - Set Meaningful Coverage Targets
strat-integration-boundaries - Test Integration at Service Boundaries
strat-e2e-critical-paths - Limit E2E Tests to Critical User Paths

How to Use

Read individual reference files for detailed explanations and code examples:

Section definitions - Category structure and impact levels
Rule template - Template for adding new rules
cycle-write-test-first - Write the Test Before the Implementation
design-aaa-pattern - Follow the Arrange-Act-Assert Pattern

For Vitest framework specifics, see vitest skill
For API mocking with MSW, see msw skill

Full Compiled Document

For the complete guide with all rules expanded: AGENTS.md

Files

SKILL.md and 47 other files (references, assets) in skills/.curated/tdd of pproenca/dot-skills.

SKILL.md
AGENTS.md
README.md
assets/templates/_template.md
metadata.json
references/_sections.md
references/assert-custom-matchers.md
references/assert-error-messages.md
references/assert-no-assertions-antipattern.md
references/assert-snapshot-testing.md
references/assert-specific-assertions.md
references/cycle-maintain-test-list.md
references/cycle-minimal-code-to-pass.md
references/cycle-refactor-after-green.md
references/cycle-small-increments.md
references/cycle-verify-test-fails-first.md
references/cycle-write-test-first.md
references/data-avoid-mystery-guests.md
… and 30 more

Open the folder on GitHubat commit cf93c57

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.

TDD compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
TDD this skillpproenca/dot-skills	214	—	~1.4k	Automated safety check: Pass	MIT	1 mo ago
Agent Harness Testing Methodologyhuiliyi37/Tianshu-harness	1.1k	—	~1k	Automated safety check: Notes	Apache-2.0	2 days ago
MoAI TDD Workflowmodu-ai/moai-adk	1.2k	—	~3.1k	Automated safety check: Pass	Apache-2.0	today
Test Coveragescott-fryxell/brayness	124	—	~1.6k	Automated safety check: Pass	MIT	9 days ago
Odc TestingDouglasNeuroInformatics/OpenDataCapture	119	—	~1.5k	Automated safety check: Notes	Apache-2.0	today
Test-Driven Development Enforcerzereight/gitlab-mcp	2k	1 repos	~904	Automated safety check: Pass	MIT	yesterday

Similar skills

Agent Harness Testing Methodology
huiliyi37/Tianshu-harness
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1.1k GitHub stars~1k tokensUpdated 2 days ago
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MoAI TDD Workflow
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Drives test-first development through the RED, GREEN, REFACTOR cycle, with a config switch that selects between TDD and a DDD workflow for existing code.
1.2k GitHub stars~3.1k tokensUpdated today
Testing & QAAuto-check passed
Test Coverage
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Testing & QAAuto-check passed
Odc Testing
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119 GitHub stars~1.5k tokensUpdated today
Testing & QAAuto-check: notes
Test-Driven Development Enforcer
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Testing & QAAuto-check passed
Building
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Questions about TDD

What does TDD do?

Test-Driven Development methodology and red-green-refactor workflow (formerly test-tdd). TDD is an agent skill from pproenca/dot-skills. Test-Driven Development methodology and red-green-refactor workflow (formerly test-tdd).

When should I use TDD?

TDD fits situations like: write tests first; test before code; red green refactor; test driven development.

How do I install TDD in Claude Code?

Run `npx skills add pproenca/dot-skills --skill tdd -a claude-code`. Or copy the skill folder (skills/.curated/tdd in pproenca/dot-skills) 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 pproenca/dot-skills --skill tdd -a codex`. Or copy the skill folder (skills/.curated/tdd in pproenca/dot-skills) 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 pproenca/dot-skills --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?

SKILL.md names no scripts, command-line tools or credentials: TDD is instructions for the agent only.

Does TDD access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. 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 MIT 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 1.4k tokens (SKILL.md is roughly 5.5k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 23k tokens, read only when the agent opens those files.

What are the alternatives to TDD?

Skills that share tags, products or a category with TDD: Agent Harness Testing Methodology (huiliyi37/Tianshu-harness, 1.1k stars), MoAI TDD Workflow (modu-ai/moai-adk, 1.2k stars), Test Coverage (scott-fryxell/brayness, 124 stars) and Odc Testing (DouglasNeuroInformatics/OpenDataCapture, 119 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains TDD?

pproenca (a GitHub user) maintains it in pproenca/dot-skills, which has 214 GitHub stars. The repository holds 182 skills in this directory. The repository was last updated on August 15, 2026.

Source: pproenca/dot-skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install TDD

Facts

At a glance

What it does

When your agent uses it

Example prompts

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Community Test-Driven Development Best Practices

When to Apply

TDD Workflow

Rule Categories by Priority

Quick Reference

1. Red-Green-Refactor Cycle (CRITICAL)

2. Test Design Principles (CRITICAL)

3. Test Isolation & Dependencies (HIGH)

4. Test Data Management (HIGH)

5. Assertions & Verification (MEDIUM)

6. Test Organization & Structure (MEDIUM)

7. Test Performance & Reliability (MEDIUM)

8. Test Pyramid & Strategy (LOW)

How to Use

Related Skills

Full Compiled Document

Files

Compare with similar skills

Similar skills

More from pproenca/dot-skills

Related

Questions about TDD