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 Miosa-osa/OSA --skill test-driven-developmentgit clone --depth 1 https://github.com/Miosa-osa/OSAWrote 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/miosa-osa/osa/test-driven-development)<a href="https://agentmods.dev/skills/miosa-osa/osa/test-driven-development"><img src="https://agentmods.dev/badge/skills/miosa-osa/osa/test-driven-development/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/miosa-osa/osa/test-driven-development"><img src="https://agentmods.dev/badge/skills/miosa-osa/osa/test-driven-development.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 | $0.00047 | $0.00340 |
| Opus 5.5 | $0.00019 | $0.00136 |
| Sonnet 5.5 | $0.00009 | $0.00068 |
| Haiku 4.5 | $0.00005 | $0.00034 |
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 1mo 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.
What it actually says
Test-Driven Development
Use tests to define the behavior before implementing it.
Red
- Identify the narrowest externally meaningful behavior.
- Find the nearest existing test style and harness.
- Write one focused test using the public interface or real user surface.
- Run it and confirm it fails for the intended reason.
- If it passes immediately, the test does not prove the requested change.
Green
- Implement the smallest production change that satisfies the behavior.
- Run the focused test.
- Run nearby tests that exercise the same module or seam.
- Keep unrelated cleanup out of the green step.
Refactor
- Remove duplication and clarify names without changing behavior.
- Keep the tests green after each meaningful change.
- Run formatting, static checks, and the proportionate broader suite.
Test quality
- Prefer observable outcomes over implementation details.
- Include meaningful failure messages for complex invariants.
- Avoid sleeps when a deterministic signal is available.
- Do not mock the behavior under test.
- For a bug, preserve the original reproduction as a regression test whenever practical.
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.
- 1mo ago First seen · 50 lines · 47 tokens per session scan A c89541cecd11
test-driven-development is a skill published in the GitHub repository Miosa-osa/OSA (78 stars, last pushed 11d ago), licensed Apache-2.0. It adds 47 tokens to every session and 340 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-08-30.
Other skills, from other repositories
test-driven-development
Use when implementing any feature or bugfix, before writing implementation code.
skill-authoring
Use when creating new skills, editing existing skills, or verifying skills work before deployment. Applies TDD methodology to skill documentation.
kotlin-testing
Kotlin testing patterns with Kotest, MockK, coroutine testing, property-based testing, and Kover coverage. Follows TDD methodology with idiomatic Kotlin practices.
systematic-debugging
4-phase root cause debugging: understand bugs before fixing.
rust-testing
Rust testing patterns including unit tests, integration tests, async testing, property-based testing, mocking, and coverage. Follows TDD methodology.
test-driven-development
TDD: enforce RED-GREEN-REFACTOR, tests before code.