tdd

tdd is a skill for Claude Code, Codex from arbiterForge/codeArbiter. It costs 73 tokens per session (2,164 once invoked), scanned A, original, AGPL-3.0.

A test-first development workflow, commonly called TDD, where tests are written and checked before implementation code is added.

In plain words
What is it for?
It is for implementing features, fixes, and refactors with tests that guide and verify the code.
Why use it?
It makes the required behavior explicit and verifies the change through separate test, coverage, and lint stages.

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/arbiterforge/codearbiter/tdd
Any agent
npx skills add arbiterForge/codeArbiter --skill tdd
Clone the repo
git clone --depth 1 https://github.com/arbiterForge/codeArbiter

Made for: Claude Code, Codex.

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/arbiterforge/codearbiter/tdd.svg)](https://agentmods.dev/skills/arbiterforge/codearbiter/tdd)
Your own site
<a href="https://agentmods.dev/skills/arbiterforge/codearbiter/tdd"><img src="https://agentmods.dev/badge/skills/arbiterforge/codearbiter/tdd.svg" alt="Measured on agentmods" height="20"></a>
Per session 73 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,164 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 $0.00073 $0.02164
Opus 5 $0.00036 $0.01082
Sonnet 5 $0.00015 $0.00433
Haiku 4.5 $0.00007 $0.00216

Measured yesterday against content hash a7adfdf9e41e, 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 yesterday.

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.

core/surface/skills/tdd/SKILL.md · 140 lines

The source is not reproduced here

Licensed AGPL-3.0

The repository is licensed AGPL-3.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.

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. yesterday First seen · 140 lines · 73 tokens per session scan A a7adfdf9e41e

Subscribe to this mod's changes

tdd is a skill published in the GitHub repository arbiterForge/codeArbiter (141 stars, last pushed yesterday), licensed AGPL-3.0. It adds 73 tokens to every session and 2,164 once invoked, about $0.0004 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 2026-09-03.

Related

Other skills, from other repositories

tdd

Workflow Phase 6 — TDD coordinator. Decides the scenario recipe and the implementation contract in main context, writes them to a state file, seeds per-worker tasks (scenario, implement, verify-tick, design-ui-tick) into the TaskList, and yields with harnessstate continue so the harness invokes each worker as its own…

friedbotstudio/baseline · 82 tokens

implement

Write the production code that makes a pre-decided set of failing tests pass, within an explicit writeset, following an explicit behavior contract. Used by /tdd Step 3 and by /swarm-dispatch workers. The caller has already decided architecture, naming, file layout, and abstraction boundaries — this skill executes that…

friedbotstudio/baseline · 98 tokens

scenario

Write executable failing tests from a recipe handed to you by the main context. Used by /tdd Step 2 and ad-hoc when a phase needs tests-first to drive implementation. Decisions about which scenarios to cover, which categories matter, and which fixtures to use are made by the caller — this skill executes that recipe…

friedbotstudio/baseline · 73 tokens

harness

End-to-end workflow orchestrator. Walks the 11-phase pipeline, invoking each phase skill in order inside an internal loop, yielding at consent gates (/approve-direction, /approve-swarm, /grant-commit), and exiting cleanly on yield/failure/done. Decides swarm-vs-solo at Phase 6. Auto-loops /tdd on integrate failures…

friedbotstudio/baseline · 110 tokens

triage

Triage an incoming request — pick the workflow entry phase (intake / spec / tdd / chore) and record the workflow statefile that the Track Guard reads.

friedbotstudio/baseline · 37 tokens

code-structure

MANDATORY skill for ALL code generation. Enforces top-down composition, consistent abstraction layers, and proper module hierarchy. Apply every time you write or modify code — in any language — no exceptions.

friedbotstudio/baseline · 43 tokens