copilot-tdd-harness: Skill for Claude Code

.github/skills/tdd-cycle-runner/SKILL.md

tdd-cycle-runner is a skill for Claude Code from mrlarson2007/copilot-tdd-harness. It costs 49 tokens per session (381 once invoked), scanned A, original, MIT.

A coordinator for one test-driven development cycle: Red, Green, Commit, and Refactor. TDD means writing a failing test, making it pass, saving the change, and then improving the code.

In plain words
What is it for?
Use it to run one scenario slice through the TDD phases, route checks through the test runner, validate each contract, and return a completion summary.
Why use it?
It keeps each change small, checks the handoffs between stages, and provides a clear escalation path when a verification fails.

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-cycle-runner/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-cycle-runner

README.md
[![agentmods](https://agentmods.dev/badge/skills/mrlarson2007/copilot-tdd-harness/tdd-cycle-runner/github.svg)](https://agentmods.dev/skills/mrlarson2007/copilot-tdd-harness/tdd-cycle-runner)
Your own site
<a href="https://agentmods.dev/skills/mrlarson2007/copilot-tdd-harness/tdd-cycle-runner"><img src="https://agentmods.dev/badge/skills/mrlarson2007/copilot-tdd-harness/tdd-cycle-runner/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-cycle-runner

Your own site · 80×15
<a href="https://agentmods.dev/skills/mrlarson2007/copilot-tdd-harness/tdd-cycle-runner"><img src="https://agentmods.dev/badge/skills/mrlarson2007/copilot-tdd-harness/tdd-cycle-runner.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 49 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 381 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 $0.00049 $0.00381
Opus 5 $0.00024 $0.00191
Sonnet 5 $0.00010 $0.00076
Haiku 4.5 $0.00005 $0.00038

Measured 9d ago against content hash 18044a34f54d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

tdd-cycle-runner 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 9d 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-cycle-runner/SKILL.md · 53 lines

What it actually says

TDD Cycle Runner Skill

Workflow

  1. Receive start_cycle contract from main orchestrator
  2. For each phase:
  • Load phase SKILL.md and asset files
  • Execute phase guidance through the loaded phase skill
  • Route every RED, GREEN, and REFACTOR verification through tdd-test-run using an explicit expected-result contract before advancing the cycle
  • Validate contract result
  • On failure, escalate to main orchestrator
  1. On completion, return cycle_complete contract

Decision Points

  • If any phase fails, escalate immediately
  • If all phases succeed, return cycle summary

Quality Criteria

  • Only minimal context passed to each phase
  • All contract handoffs validated
  • No direct communication with main orchestrator by phase skill executions
  • Progressive disclosure enforced
  • Any rollback after a failed verification is limited to the scoped files named in the test_run_request contract

Completion Checks

  • All contracts for the cycle are satisfied
  • All phase outputs are validated
  • Escalation path is tested
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. 9d ago First seen · 53 lines · 49 tokens per session scan A 18044a34f54d

Subscribe to this mod's changes

tdd-cycle-runner is a skill published in the GitHub repository mrlarson2007/copilot-tdd-harness (5 stars, last pushed 3mo ago), licensed MIT. It adds 49 tokens to every session and 381 once invoked, about $0.0002 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.