tdd

A test-driven development skill. TDD means writing a failing test first, making the code pass, and then improving the code.

In plain words
What is it for?
It is for implementing features, fixing bugs and incidents, refactoring, and deleting legacy code using a test-first process.
Why use it?
It helps catch bugs and guide changes before implementation grows, including during refactoring or removal of old code.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/somebody32/agents/tdd
Any agent
npx skills add somebody32/agents --skill tdd
Clone the repo
git clone --depth 1 https://github.com/somebody32/agents

Made for: Claude Code, Codex.

Per session 107 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,610 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
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 $0.00107 $0.04610
Opus 5 $0.00053 $0.02305
Sonnet 5 $0.00021 $0.00922
Haiku 4.5 $0.00011 $0.00461

Measured 2d ago against content hash b6b0779b2113, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

tdd scanned grade A with 1 finding 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 2d 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

// ❌ One fetch(endpoint, options) → mock must branch on the endpoint
skills/tdd/SKILL.md · 429 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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. 2d ago First seen · 429 lines · 107 tokens per session scan A b6b0779b2113

Subscribe to this mod's changes

tdd is a skill published in the GitHub repository somebody32/agents (5 stars, last pushed 5d ago), with no licence file. It adds 107 tokens to every session and 4,610 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Related

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