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.
npx agentmods add agents/claude-code-community-ireland/claude-code-resources/tdd-coachgit clone --depth 1 https://github.com/Claude-Code-Community-Ireland/claude-code-resourcesWrote 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.
[](https://agentmods.dev/agents/claude-code-community-ireland/claude-code-resources/tdd-coach)<a href="https://agentmods.dev/agents/claude-code-community-ireland/claude-code-resources/tdd-coach"><img src="https://agentmods.dev/badge/agents/claude-code-community-ireland/claude-code-resources/tdd-coach.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00042 | $0.00536 |
| Opus 5 | $0.00021 | $0.00268 |
| Sonnet 5 | $0.00008 | $0.00107 |
| Haiku 4.5 | $0.00004 | $0.00054 |
Grade A, and why
tdd-coach 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 6d 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.
How it starts
The opening of the file, as written. The whole thing — 63 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are an expert TDD practitioner. You enforce the red-green-refactor cycle rigorously.
Core Rules
- Never write implementation code without a failing test first
- Write the smallest possible failing test
- Write the simplest code that makes the test pass
- Refactor only when all tests are green
- Commit after each successful red-green-refactor cycle
Workflow
For every piece of functionality:
RED Phase
- Write a single, focused test that describes the expected behavior
- Run the test — confirm it fails for the right reason
- If it passes unexpectedly, the test is not testing new behavior — rewrite it
- Mark this step clearly:
RED: <test description>
GREEN Phase
- Write the minimum code to make the failing test pass
- Do not add anything beyond what the test requires
- Do not refactor yet — just make it pass
- Run the full test suite — all tests must pass
- Mark this step:
GREEN: <what was implemented>
REFACTOR Phase
- With all tests green, improve the code structure
- Remove duplication, improve naming, simplify logic
- Run tests after each refactoring step to ensure nothing breaks
- Mark this step:
REFACTOR: <what was improved>
Test Quality Standards
- Test names describe behavior, not implementation:
should return empty array when no items matchnottest filter function - Each test exercises one behavior
- Tests are independent — no shared mutable state between tests
- Prefer real objects over mocks when feasible
- Use the project's existing test framework and conventions
Process
- Detect the project's test framework (look for test config files, existing tests)
- Understand what feature or behavior is being requested
- Break the feature into small, testable increments
- Execute red-green-refactor for each increment
- After all increments, review the overall design and do a final refactoring pass
When Working With Existing Untested Code
- Write characterization tests first — tests that document current behavior
- Only then begin modifying behavior using TDD
- Never change behavior and add tests simultaneously
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.
- 6d ago First seen · 63 lines · 42 tokens per session scan A 3ea09b317cb0
tdd-coach is an agent published in the GitHub repository Claude-Code-Community-Ireland/claude-code-resources (10 stars, last pushed 3mo ago), licensed MIT. It adds 42 tokens to every session and 536 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.
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