Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/Anyesh/skillprobenpx agentmods add skills/anyesh/skillprobe/write-testsWrote 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/anyesh/skillprobe/write-tests)<a href="https://agentmods.dev/skills/anyesh/skillprobe/write-tests"><img src="https://agentmods.dev/badge/skills/anyesh/skillprobe/write-tests/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/anyesh/skillprobe/write-tests"><img src="https://agentmods.dev/badge/skills/anyesh/skillprobe/write-tests.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 | $0.00041 | $0.02448 |
| Opus 5.5 | $0.00016 | $0.00979 |
| Sonnet 5.5 | $0.00008 | $0.00490 |
| Haiku 4.5 | $0.00004 | $0.00245 |
Grade A, and why
write-tests 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.
How it starts
The opening of the file, as written. The whole thing — 249 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Writing skillprobe Tests
Generate YAML test files for skillprobe. Always read the skill content first before writing tests.
When asked to write tests for a skill, generate BOTH files unless the user asks for only one:
- A behavioral test file (for
skillprobe run) - An activation test file (for
skillprobe activation)
Behavioral Tests (for skillprobe run)
Test what the model DOES when the skill is loaded.
harness: claude-code # or cursor
model: claude-haiku-4-5-20251001
timeout: 120
skill: ./path/to/skill # directory with SKILL.md, or a .md file
scenarios:
- name: "descriptive name"
steps:
- prompt: "what the user would type"
assert:
- type: contains
value: "expected text"
Activation Tests (for skillprobe activation)
Test whether the skill LOADS for relevant prompts and stays quiet for irrelevant ones. This is a separate YAML format from behavioral tests.
harness: claude-code
model: claude-haiku-4-5-20251001
timeout: 60
skill: ./path/to/skill
activation:
skill_name: my-skill
should_activate:
- "prompt that should trigger this skill"
- "another relevant prompt"
should_not_activate:
- "completely unrelated prompt"
- "another unrelated prompt"
The activation key replaces scenarios. These are two different file formats loaded by different commands (skillprobe run vs skillprobe activation). Never put both keys in the same file. skillprobe will either ignore one silently or fail to parse the file.
Bad:
skill: ./skills/commit
activation:
skill_name: commit
should_activate:
- "commit my changes"
scenarios:
- name: "commit happens"
steps:
- prompt: "commit"
assert:
- type: contains
value: "commit"
Pick one format per file.
Testing skill combinations
Some tests need to load more than one skill at a time, either because you are probing interactions between skills or because the scenario legitimately needs both. Use a skills: list at the suite level instead of the singular skill::
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 · 249 lines · 41 tokens per session scan A 6a952c166072
write-tests is a skill published in the GitHub repository Anyesh/skillprobe (6 stars, last pushed 6mo ago), licensed MIT. It adds 41 tokens to every session and 2,448 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 2026-08-31.
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