What is test-driven-development?

A test-driven development (TDD) workflow that starts with a failing test, adds the smallest code needed to pass it, then improves the code while tests remain passing.

Use it when building or changing code that should be covered by tests, following the cycle of writing tests, making them pass, and refactoring.

It helps catch mistakes early and keeps code changes tied to a clear expected result.

How plipowczan/claude-piv-skeleton configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to plipowczan/claude-piv-skeleton. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/plipowczan/claude-piv-skeleton/main/.claude/skills/test-driven-development/SKILL.md

Clone the repo

git clone --depth 1 https://github.com/plipowczan/claude-piv-skeleton

Made for: Claude Code.

Or install piv-speckit, the plugin that ships this one along with the rest of its 6 skills, 16 commands.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/plipowczan/claude-piv-skeleton/test-driven-development.svg)](https://agentmods.dev/skills/plipowczan/claude-piv-skeleton/test-driven-development)

Your own site

<a href="https://agentmods.dev/skills/plipowczan/claude-piv-skeleton/test-driven-development"><img src="https://agentmods.dev/badge/skills/plipowczan/claude-piv-skeleton/test-driven-development.svg" alt="Measured on agentmods" height="20"></a>

Per session 12 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 95 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00012	$0.00095
Opus 5	$0.00006	$0.00048
Sonnet 5	$0.00002	$0.00019
Haiku 4.5	$0.00001	$0.00010

Measured 8d ago against content hash c6a42d262d0d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

test-driven-development scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/skills/test-driven-development/SKILL.md · 16 lines

What it actually says

TDD Skill

RED: Write failing test FIRST GREEN: Minimal code to pass REFACTOR: Improve while green

❌ Code before tests → DELETE

Read .claude/reference/skills-full/tdd-full.md

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

8d ago First seen · 16 lines · 12 tokens per session scan A c6a42d262d0d

Subscribe to this mod's changes

test-driven-development is a skill published in the GitHub repository plipowczan/claude-piv-skeleton (4 stars, last pushed 7mo ago), licensed MIT. It adds 12 tokens to every session and 95 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

TDD Testing

engram-testing-coverage

TDD and coverage standards for Engram. Trigger: When implementing behavior changes in any package.

Gentleman-Programming/engram · 25 tokens

nw-fp-clojure

Clojure language-specific patterns, data-first modeling, REPL-driven development, and spec.

nWave-ai/nWave · 25 tokens

strict-tdd

Strict RED->GREEN->REFACTOR test-driven development with enforcement. Never write production code before a failing test. Atomic commits per TDD cycle.

a5c-ai/babysitter · 34 tokens

mobiai-mobile-tdd

You MUST use this before writing any implementation code for a mobile feature, bug fix, refactor, or behavior change. Tests come before implementation — no exceptions.

ArisGuimera/MobiAI-Core · 38 tokens

tdd

This skill should be used when the user wants to implement features or fix bugs using test-driven development. Enforces the RED-GREEN-REFACTOR cycle with vertical slicing, context isolation between test writing and implementation, human checkpoints, and auto-test feedback loops. Uses multi-agent orchestration with the…

glebis/claude-skills · 92 tokens

conductor-implement

Execute tasks from a track's implementation plan following TDD workflow.

rmyndharis/antigravity-skills · 17 tokens

claude-piv-skeleton: Skill for Claude Code