copilot-tdd-harness: Skill for Claude Code

.github/skills/tdd-setup/SKILL.md

tdd-setup is a skill for Claude Code from mrlarson2007/copilot-tdd-harness. It costs 53 tokens per session (999 once invoked), scanned A, original, MIT.

A guide for improving code and tests after the tests pass in a TDD cycle. It keeps behavior unchanged while improving readability and introducing helpers or builders when they make future tests easier to write.

In plain words
What is it for?
Use it to refactor an implemented change, review surrounding code, improve test structure, and verify the focused and broader test suites.
Why use it?
It reduces complexity after implementation without hiding regressions. It also uses the project's documented style and requires evidence that the touched tests still pass.

Skill for Claude Code

Written for Claude Code: user-invocable in frontmatter.

This is mrlarson2007/copilot-tdd-harness's own configuration. It tells Claude Code how to work on copilot-tdd-harness itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything copilot-tdd-harness configures →

Reuse

Borrowing it

Nothing to install: this file belongs to mrlarson2007/copilot-tdd-harness. 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/mrlarson2007/copilot-tdd-harness/master/.github/skills/tdd-setup/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/mrlarson2007/copilot-tdd-harness

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-setup

README.md
[![agentmods](https://agentmods.dev/badge/skills/mrlarson2007/copilot-tdd-harness/tdd-setup.svg)](https://agentmods.dev/skills/mrlarson2007/copilot-tdd-harness/tdd-setup)
Your own site
<a href="https://agentmods.dev/skills/mrlarson2007/copilot-tdd-harness/tdd-setup"><img src="https://agentmods.dev/badge/skills/mrlarson2007/copilot-tdd-harness/tdd-setup.svg" alt="Measured on agentmods" height="20"></a>
Per session 53 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 999 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00053 $0.00999
Opus 5 $0.00026 $0.00500
Sonnet 5 $0.00011 $0.00200
Haiku 4.5 $0.00005 $0.00100

Measured 7d ago against content hash bd95c328a815, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

tdd-setup 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.

.github/skills/tdd-setup/SKILL.md · 101 lines

How it starts

The opening of the file, as written. The whole thing — 101 lines — stays where its author put it; the contents beside it link to each section on GitHub.

tdd-setup

Use this skill when the repository needs project-specific TDD configuration.

Goals

Generate:

  • .github/instructions/tdd-patterns.instructions.md
  • .github/skills/tdd-red/assets/project-testing-patterns.md
  • .github/skills/tdd-green/assets/project-code-style-patterns.md
  • .github/skills/tdd-refactor/assets/project-refactor-patterns.md

These three phase asset files are canonical placeholders and must always exist, even before final pattern extraction.

Pattern Extraction Step

  1. Ensure canonical placeholder files exist for RED, GREEN, and REFACTOR style guides.
  2. Prompt the user to select or specify exemplar test files and production code files that best represent the project's preferred style and conventions.
  3. Use LLM-powered analysis to extract:
  • Test structure, naming, and assertion patterns from the exemplar test files (for RED)
  • Code style, idioms, and formatting conventions from the exemplar production files (for GREEN)
  • Refactoring and surrounding-code consistency patterns from both (for REFACTOR)
  1. Summarize the extracted patterns and present them to the user for confirmation or editing.
  2. After confirmation, update:
  • .github/skills/tdd-red/assets/project-testing-patterns.md
  • .github/skills/tdd-green/assets/project-code-style-patterns.md
  • .github/skills/tdd-refactor/assets/project-refactor-patterns.md

If the user does not provide example files, run interview-only mode.

Interview Workflow

  1. Present extracted patterns first, then ask for confirmation or corrections.
  2. If a value or pattern is missing, ask:
  • What test runner do you use?
  • What build command should the agent use for validation when a build step is needed?
  • Where are your test files?
  • What naming convention do you use for test methods or test cases?
  • What assertion library do you use?
  • What mocking approach or mocking library do you use?
  • What testing patterns should RED follow (for example AAA, table-driven, Given-When-Then naming)?
  • What implementation/code-style patterns should GREEN follow (for example naming, formatting, guard clauses, error handling conventions)?
  • What refactoring style patterns should REFACTOR follow (for example surrounding-code consistency, helper extraction thresholds, readability priorities)?
  • Are there project-specific testing patterns for time, logging, HTTP, database, or other dependencies?

Read the full file on GitHub · 101 lines

Files

What ships with it

4 files 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 First seen · 101 lines · 53 tokens per session scan A bd95c328a815

Subscribe to this mod's changes

tdd-setup is a skill published in the GitHub repository mrlarson2007/copilot-tdd-harness (5 stars, last pushed 3mo ago), licensed MIT. It adds 53 tokens to every session and 999 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.