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 skills/metaspartan/cybara/test-driven-developmentnpx skills add metaspartan/cybara --skill test-driven-developmentgit clone --depth 1 https://github.com/metaspartan/cybaraWrote 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/metaspartan/cybara/test-driven-development)<a href="https://agentmods.dev/skills/metaspartan/cybara/test-driven-development"><img src="https://agentmods.dev/badge/skills/metaspartan/cybara/test-driven-development.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 | $0.00037 | $0.00386 |
| Opus 5 | $0.00018 | $0.00193 |
| Sonnet 5 | $0.00007 | $0.00077 |
| Haiku 4.5 | $0.00004 | $0.00039 |
Grade A, and why
test-driven-development 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.
What it actually says
Test-Driven Development (TDD)
Write the test first. It forces precise specifications and gives a free regression net.
Red → Green → Refactor
- Red. Write ONE small test for the behavior you want. Run it. It must FAIL (and fail for the right reason — an assertion, not a compile error in unrelated code).
- Green. Write the minimum code to make that test pass. No more, no less. Run it.
- Refactor. Clean up duplication while keeping tests green. Re-run after each change.
Repeat with the next smallest increment.
Rules of thumb
- Test behavior, not implementation. Prefer public API; don't poke private internals.
- One assertion concept per test. If "and" appears in the test name, consider splitting.
- Name tests like
it("returns X when Y")/should do Z when …. - If a bug fix, write the test that reproduces the bug FIRST (see
systematic-debugging). - Don't write tests that depend on wall-clock, random, or network unless you stub them.
Running tests
- Match the project's framework and command (
bun test,pytest,go test, …). - For Bun projects:
bun test(perAGENTS.md, Bun is the only JS runner).
When TDD is overkill
- Throwaway exploration / spikes — write the test after you know the shape.
- Pure UI tweaks with no logic — a visual check is fine.
TDD pays off most for: parsers, state machines, financial/permission logic, and anything with many edge cases.
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.
- yesterday First seen · 37 lines · 37 tokens per session scan A e87fb888e1f9
test-driven-development is a skill published in the GitHub repository metaspartan/cybara (25 stars, last pushed yesterday), licensed MIT. It adds 37 tokens to every session and 386 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 2026-09-03.
Other skills, from other repositories
08-debug
Reproduce and fix a known bug, or find an unknown root cause by hypothesis validation. Use when the user wants to fix a bug, find why something breaks, or reopen a stuck investigation. Not for building a feature or reviewing a diff.
Test Driven Development
Drive behavior changes through a failing test, the smallest working implementation, and then cleanup once the behavior is locked.
tdd-implementation
Use when implementing any code change for a task – new behavior, a bugfix, or a revision after review – before writing the production code. Defines the failing-test-first cycle, public-seam testing, vertical slices, scaffold and infra handling, and counters to common excuses for tests-after-code.
superpowers-test-driven-development
Skill "superpowers-test-driven-development" from KornLabs/truss, covering test-driven development (tdd), when to use, the iron law, red-green-refactor and red - write failing test.
test-driven-development
TDD: enforce RED-GREEN-REFACTOR, tests before code.
smoke-test
End-to-end smoke test skill for DeerFlow. Guides through: 1) Pulling latest code, 2) Docker OR Local installation and deployment (user preference, default to Local if Docker network issues), 3) Service availability verification, 4) Health check, 5) Final test report. Use when the user says "run smoke test", "smoke…