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 skills add biggora/claude-plugins-registry --skill tdd-red-greengit clone --depth 1 https://github.com/biggora/claude-plugins-registryWrote 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/skills/biggora/claude-plugins-registry/tdd-red-green)<a href="https://agentmods.dev/skills/biggora/claude-plugins-registry/tdd-red-green"><img src="https://agentmods.dev/badge/skills/biggora/claude-plugins-registry/tdd-red-green/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.
<a href="https://agentmods.dev/skills/biggora/claude-plugins-registry/tdd-red-green"><img src="https://agentmods.dev/badge/skills/biggora/claude-plugins-registry/tdd-red-green.svg" alt="Reviewed on agentmods" width="80" 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 | $0.00088 | $0.00939 |
| Opus 5 | $0.00044 | $0.00469 |
| Sonnet 5 | $0.00018 | $0.00188 |
| Haiku 4.5 | $0.00009 | $0.00094 |
Grade A, and why
tdd-red-green 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.
How it starts
The opening of the file, as written. The whole thing — 65 lines — stays where its author put it; the contents beside it link to each section on GitHub.
TDD Red Green
Implement one observable behavior at a time through a verified RED → GREEN → REFACTOR loop. Treat no change as a correct outcome when the reported bug does not reproduce.
Do not use this workflow for documentation-only, copy-only, formatting-only, or other changes that cannot alter behavior.
Establish Safe Ground
- Read repository instructions, the requested acceptance criterion, test configuration, and project-defined test commands.
- Inspect
git statusand relevant diffs before editing. Separate pre-existing user changes from paths owned by this task; preserve all user work. - Classify the request as a bug, a new behavior, or behavior that may already be correct. Stop and clarify contradictory or untestable criteria.
- Select one observable behavior and the narrowest appropriate test level. Split broader work before writing code.
- Read TDD handoff and checkpoints when handing off a critical acceptance test, recording cycle evidence, recovering from a failed attempt, or pausing work.
Reproduce or Abstain for Bugs
- Translate the report into a relevant automated test that would fail only when the reported defect exists.
- Run the test against the unchanged implementation.
- Continue only when the test fails for the intended behavioral reason.
- If current behavior satisfies the criterion, stop without modifying production code. Report the test or reproduction command, observed output, and why it proves a no-change result.
- If the defect cannot be reproduced reliably, stop and report the missing evidence or environment requirement. Do not invent a patch.
Run One RED → GREEN → REFACTOR Cycle
RED
- Add one focused test for the selected behavior. For a critical acceptance criterion, use a fresh test-author or session when available; provide only the criterion, public contract, repository test conventions, and allowed test paths—not an implementation plan or prior implementation history.
- Run the narrowest command that executes the new test.
- Confirm that the intended assertion fails because the behavior is absent or wrong. Reject syntax errors, import failures, broken fixtures, unrelated failures, and tests that pass immediately as RED evidence.
- Record the command, expected assertion, actual failure, and causal explanation before changing production code.
What ships with it
1 file 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.
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.
- 9d ago First seen · 65 lines · 88 tokens per session scan A d7eb1cf714c3
tdd-red-green is a skill published in the GitHub repository biggora/claude-plugins-registry (2 stars, last pushed 11d ago), licensed MIT. It adds 88 tokens to every session and 939 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 2026-08-31.
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