tdd

tdd is a skill for Claude Code from citypaul/.dotfiles. It costs 265 tokens per session (4,937 once invoked), scanned A, original, no licence file.

A test-first workflow for changing production behavior: write a failing test, make it pass, then improve the code while keeping the test passing. It adds mutation testing or another form of evidence at the final pull-request readiness check.

In plain words
What is it for?
Use it before adding features, fixing bugs, or changing anything users can observe. It does not apply to changes that only alter internal code without changing behavior.
Why use it?
It gives feature work and bug fixes a repeatable order, with tests showing what behavior must work before the code is considered ready.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

Good fit Use it before adding features, fixing bugs, or changing anything users can observe. It does not apply to changes that only alter internal code without changing behavior.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/citypaul/.dotfiles/tdd
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add citypaul/.dotfiles --skill tdd
Clone the repo
git clone --depth 1 https://github.com/citypaul/.dotfiles

Made for: Claude Code.

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.

agentmods badge for tdd

README.md
[![agentmods](https://agentmods.dev/badge/skills/citypaul/.dotfiles/tdd/github.svg)](https://agentmods.dev/skills/citypaul/.dotfiles/tdd)
Your own site
<a href="https://agentmods.dev/skills/citypaul/.dotfiles/tdd"><img src="https://agentmods.dev/badge/skills/citypaul/.dotfiles/tdd/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for tdd

Your own site · 80×15
<a href="https://agentmods.dev/skills/citypaul/.dotfiles/tdd"><img src="https://agentmods.dev/badge/skills/citypaul/.dotfiles/tdd.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 265 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,937 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 unknown 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00265 $0.04937
Opus 5 $0.00133 $0.02469
Sonnet 5 $0.00053 $0.00987
Haiku 4.5 $0.00026 $0.00494

Measured 7d ago against content hash cb07fd27be19, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

tdd 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 7d 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/.claude/skills/tdd/SKILL.md · 289 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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.

  1. 7d ago Changed · +101 tokens per session cb07fd27be19
  2. 9d ago Changed · +52 tokens per session 59e4c44f31bd
  3. 12d ago First seen · 289 lines · 112 tokens per session scan A 8311aa10ef6f

Subscribe to this mod's changes

tdd is a skill published in the GitHub repository citypaul/.dotfiles (730 stars, last pushed yesterday), with no licence file. It adds 265 tokens to every session and 4,937 once invoked, about $0.0013 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 2026-08-30.