Use when implementing any feature or bugfix, before writing implementation code.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Test-Driven Development (TDD)
## Overview
Write the test first. Watch it fail. Write minimal code to pass.
**Core principle:** If you didn't watch the test fail, you don't know if it tests the right thing.
**Violating the letter of the rules is violating the spirit of the rules.**
## When to Use
**Always:**
- New features
- Bug fixes
- Refactoring
- Behavior changes
**Exceptions (ask your human partner):**
- Throwaway prototypes
- Generated code
- Configuration files
Thinking "skip TDD just this once"? Stop. That's rationalization.
## The Iron Law
```
NO PRODUCTION CODE WITHOUT A FAILING TEST FIRST
```
Write code before the test? Delete it. Start over.
**No exceptions:**
- Don't keep it as "reference"
- Don't "adapt" it while writing tests
- Don't look at it
- Delete means delete
Implement fresh from tests. Period.
## Red-Green-Refactor
```dot
digraph tdd_cycle {
rankdir=LR;
red [label="RED\nWrite failing test", shape=box, style=filled, fillcolor="#ffcccc"];
verify_red [label="Verify fails\ncorrectly", shape=diamond];
green [label="GREEN\nMinimal code", shape=box, style=filled, fillcolor="#ccffcc"];
…
The line at the top of this page pins the label v1.0.1, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
GET https://markdownregistry.com/api/v1/artifacts/art_3ctiztkpbcx2cjxa
GET https://markdownregistry.com/api/v1/resolve?ref=sodiumjoe/dotfiles/test-driven-development
GET https://markdownregistry.com/api/v1/blob/e68809538d77c315fe4372f3fb3306f66117f84f54272cb04ebad6026a6a7eb1
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
sodiumjoe/dotfiles · home/.agents/skills/brainstorming/SKILL.md · You MUST use this before any creative work - creating features, building components, adding functionality, or modifying…
sodiumjoe/dotfiles · home/.agents/skills/dispatching-parallel-agents/SKILL.md · Use when facing 2+ independent tasks that can be worked on without shared state or sequential dependencies
sodiumjoe/dotfiles · home/.agents/skills/executing-plans/SKILL.md · Use when executing an implementation plan in the current session as the implementer yourself — your human partner chose…
sodiumjoe/dotfiles · home/.agents/skills/finishing-a-development-branch/SKILL.md · Use when implementation is complete, all tests pass, and you need to decide how to integrate the work
sodiumjoe/dotfiles · home/.agents/skills/neovim-review/SKILL.md · Use when the user invokes /neovim-review for a pull request or a local :Review session in Neovim.
sodiumjoe/dotfiles · home/.agents/skills/neovim/SKILL.md · Interact with a running neovim instance over RPC — open files, show diffs, execute Lua. Use when you need to open a…
sodiumjoe/dotfiles · home/.agents/skills/receiving-code-review/SKILL.md · Use when receiving code review feedback, before implementing suggestions, especially if feedback seems unclear or…
sodiumjoe/dotfiles · home/.agents/skills/requesting-code-review/SKILL.md · Use when completing tasks, implementing major features, or before merging to verify work meets requirements
sodiumjoe/dotfiles · home/.agents/skills/subagent-driven-development/SKILL.md · Use when executing implementation plans with independent tasks in the current session
sodiumjoe/dotfiles · home/.agents/skills/systematic-debugging/SKILL.md · Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes
sodiumjoe/dotfiles · home/.agents/skills/using-git-worktrees/SKILL.md · Use when starting feature work that needs isolation from current workspace or before executing implementation plans -…
addyosmani/agent-skills · skills/test-driven-development/SKILL.md · Drives development with tests using the red-green-refactor loop. Use when implementing any logic, fixing any bug, or…
mvschwarz/openrig · skills/_canonical/process/test-driven-development/SKILL.md · Use when implementing any feature or bugfix, before writing implementation code
mvschwarz/openrig · packages/daemon/specs/agents/shared/skills/process/test-driven-development/SKILL.md · Use when implementing any feature or bugfix, before writing implementation code
cbrock84/headcount · plugins/technology/skills/test-driven-development/SKILL.md · Drives implementation by writing a failing test first, then the smallest code that passes it. Use this before writing…
a5c-ai/babysitter · library/methodologies/superpowers/skills/test-driven-development/SKILL.md · Use when implementing any feature or bugfix, before writing implementation code. Enforces RED-GREEN-REFACTOR cycle.
a5c-ai/babysitter · library/methodologies/rpikit/skills/test-driven-development/SKILL.md · Test-first development practice where test specifications are written before production code, integrated into plan…
