tdd

A test-driven development skill for implementing behaviour from an existing tree of tests. TDD means writing or using tests to guide code in repeated red, green, and refactor steps.

In plain words
What is it for?
Writing code or tests, fixing failing tests, and implementing missing behaviour from test trees using an outside-in approach.
Why use it?
It gives implementation work a concrete feedback loop and helps close gaps between the expected behaviour and the code.

Skill for Claude CodeCodex

Part of the contree plugin — 15 skills, 2 hooks shipped together

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/elimydlarz/claude-code-plugins/tdd
Any agent
npx skills add elimydlarz/claude-code-plugins --skill tdd
Clone the repo
git clone --depth 1 https://github.com/elimydlarz/claude-code-plugins

Made for: Claude Code, Codex.

Or install contree, the plugin that ships this one along with the rest of its 15 skills, 2 hooks.

Per session 50 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 969 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. 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 $0.00050 $0.00969
Opus 5 $0.00025 $0.00485
Sonnet 5 $0.00010 $0.00194
Haiku 4.5 $0.00005 $0.00097

Measured 2d ago against content hash 758a7cbeb731, 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 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 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.

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.

contree/skills/tdd/SKILL.md · 74 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 · 74 lines · 50 tokens per session scan A 758a7cbeb731

Subscribe to this mod's changes

tdd is a skill published in the GitHub repository elimydlarz/claude-code-plugins (5 stars, last pushed 1mo ago), with no licence file. It adds 50 tokens to every session and 969 once invoked, about $0.0003 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.

Related

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