Borrowing it
Nothing to install: this file belongs to extra-org/extra. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/extra-org/extra/main/.claude/skills/testing/SKILL.mdgit clone --depth 1 https://github.com/extra-org/extraWrote 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/extra-org/extra/testing)<a href="https://agentmods.dev/skills/extra-org/extra/testing"><img src="https://agentmods.dev/badge/skills/extra-org/extra/testing/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/extra-org/extra/testing"><img src="https://agentmods.dev/badge/skills/extra-org/extra/testing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00034 | $0.01144 |
| Opus 5.5 | $0.00014 | $0.00458 |
| Sonnet 5.5 | $0.00007 | $0.00229 |
| Haiku 4.5 | $0.00003 | $0.00114 |
Grade A, and why
testing 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 2mo 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 — 121 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Skill: Testing
Purpose
Define how to write and run tests for this Python project so that every meaningful behavior is covered by fast, deterministic, behavior-focused tests that never touch real external systems.
When to Use This Skill
- Adding or changing any behavior (tests accompany behavior — almost always).
- Fixing a bug (add a regression test first).
- Working on the test suite or quality gate (task
0012). - Reviewing whether a change is adequately tested.
Files to Read First
AGENTS.mddocs/DEVELOPMENT_WORKFLOW.mdpyproject.toml([tool.pytest.ini_options])- The skill for the area under test (runtime, prompts, plugins, tools, etc.).
Core Principles
- Use
pytest. Tests live undertests/, mirroringsrc/agentplatform/. - Test behavior through public interfaces, not private implementation details (test internals only when there is no public seam).
- No real external systems in unit tests: never call real LLMs, real MCP servers, real databases, or third-party APIs. Mock/fake them.
- Integration tests only when explicitly requested, and still without real secrets or live third-party calls — use fakes/local stand-ins.
- Deterministic: control time, randomness, and ordering.
- Regression tests for bugs: every fixed bug gets a test that fails before the fix.
Process
- Pick the category (see below) for what you are testing.
- Arrange with fixtures for repeated setup (specs, compiled graphs, fake
resolver/access plugins, fake tools). Use
@pytest.mark.parametrizefor input variations. - Mock external boundaries (LLM/MCP/DB/HTTP) at the adapter seam, not deep inside.
- Write behavior assertions: given input, assert observable output/effects.
- Cover negatives and security: invalid YAML/validation errors, missing required prompt variables, denied protected-node access, plugin errors.
- Run
make test(andmake checkfor the full gate). Fix failures.
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.
- 2mo ago First seen · 121 lines · 34 tokens per session scan A 30d38b3f8142
testing is a skill published in the GitHub repository extra-org/extra (117 stars, last pushed 5d ago), licensed MIT. It adds 34 tokens to every session and 1,144 once invoked, about $0.0001 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.
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