test-driven-development SKILL.md skillA

test-driven-development from cedaniel200/atlas-template is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.

mdr add cedaniel200/atlas-template/test-driven-development@git:20261021.fb93aad

Pins git:20261021.fb93aad in mdr.lock. Pin the fingerprint instead.

Audit grade

A, 17 of 17 checks passed

Kind

SKILL.md skill

Repository

cedaniel200/atlas-template

Path

.agents/skills/test-driven-development/SKILL.md

Versions recorded

2

Latest version

git:20261021.fb93aad, committed Oct 21, 2026

First version recorded

Oct 21, 2026

Size

9,907 bytes

Repository stars

3

License

MIT

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"];
…

Read the whole file at its exact version.

How to install

mdr add cedaniel200/atlas-template/test-driven-development@sha256:1124b9006ddfe5d0

[![mdr](https://markdownregistry.com/badge/art_yqtcul7ohhs4nzea.svg)](https://markdownregistry.com/a/art_yqtcul7ohhs4nzea)

Versions

The registry has recorded 2 versions of this file, all committed on Oct 21, 2026.

Audit of the latest version

Source

API

GET https://markdownregistry.com/api/v1/artifacts/art_yqtcul7ohhs4nzea
GET https://markdownregistry.com/api/v1/resolve?ref=cedaniel200/atlas-template/test-driven-development
GET https://markdownregistry.com/api/v1/blob/1124b9006ddfe5d0c719ff9c06be0f91979b6adf7320aad338086532c83ffd1a

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.

Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.

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