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.
git clone --depth 1 https://github.com/PolicyEngine/policyengine-claudeWrote 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/commands/policyengine/policyengine-claude/write-tests)<a href="https://agentmods.dev/commands/policyengine/policyengine-claude/write-tests"><img src="https://agentmods.dev/badge/commands/policyengine/policyengine-claude/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/commands/policyengine/policyengine-claude/write-tests"><img src="https://agentmods.dev/badge/commands/policyengine/policyengine-claude/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 | $0.00015 | $0.00772 |
| Opus 5.5 | $0.00006 | $0.00309 |
| Sonnet 5.5 | $0.00003 | $0.00154 |
| Haiku 4.5 | $0.00002 | $0.00077 |
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 — 93 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Write unit tests
Write well-structured unit tests that match the conventions the target repository actually uses — discover them from existing tests, never impose an external template.
Important: This command is for frontend apps, APIs, SDKs, and standalone tools. It is
NOT for country model packages (policyengine-us, policyengine-uk, etc.), which use
YAML-based tests — for those, load the policyengine-model-development skill
(references/tests.md) and use the test-creator agent instead.
Step 1: Identify target files
Ask the user which file(s) to test. If none specified, ask:
Which source file(s) should I write tests for?
Read each source file thoroughly before writing any tests. Understand:
- All exported functions, classes, components, and their signatures
- Happy path behavior
- Error handling and edge cases
- Dependencies that need mocking
Step 2: Detect the framework and the repo's real conventions
| Indicator | Framework |
|---|---|
vitest in package.json |
Vitest |
pytest in pyproject.toml |
pytest |
jest in package.json |
Jest (legacy repos) |
Then read 2-3 existing test files near your target and copy their observed conventions:
directory layout, file naming, describe/test phrasing, mock style, and any shared
test-utils imports. In policyengine-app-v2, for example, tests live under
app/src/tests/ as Name.test.ts(x) — plain describe/test names, no
given/when/then scaffolding, no separate fixtures tree. Other repos differ; the
existing tests are the spec. If a project-level test CLAUDE.md or config exists, it
overrides everything here.
Step 3: Write test files
Place and name new tests exactly as the repo's existing tests do. Whatever the naming style, every test file must cover:
- Happy path
- Edge cases (zero, empty, null, boundary values)
- Expected error/failure paths
- Component tests: user-visible behavior (render output, interactions), not implementation details
Extract shared constants/mocks into the repo's established pattern (inline consts at
the top of the test file, or the repo's test-utils module — whichever neighbors use).
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 · 93 lines · 15 tokens per session scan A fff40f6bd0a0
write-tests is a command published in the GitHub repository PolicyEngine/policyengine-claude (32 stars, last pushed 2d ago), licensed MIT. It adds 15 tokens to every session and 772 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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