Borrowing it
Nothing to install: this file belongs to Anselmoo/mcp-ai-agent-guidelines. 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/Anselmoo/mcp-ai-agent-guidelines/main/.github/instructions/coverage-guard.instructions.mdgit clone --depth 1 https://github.com/Anselmoo/mcp-ai-agent-guidelinesWrote 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/instructions/anselmoo/mcp-ai-agent-guidelines/coverage-guard)<a href="https://agentmods.dev/instructions/anselmoo/mcp-ai-agent-guidelines/coverage-guard"><img src="https://agentmods.dev/badge/instructions/anselmoo/mcp-ai-agent-guidelines/coverage-guard/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/instructions/anselmoo/mcp-ai-agent-guidelines/coverage-guard"><img src="https://agentmods.dev/badge/instructions/anselmoo/mcp-ai-agent-guidelines/coverage-guard.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 | $0.00605 | $0.00605 |
| Opus 5 | $0.00302 | $0.00302 |
| Sonnet 5 | $0.00121 | $0.00121 |
| Haiku 4.5 | $0.00060 | $0.00060 |
Grade A, and why
mcp-ai-agent-guidelines coverage-guard.instructions.md 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 8d 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 — 49 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Coverage Guard: New TypeScript Must Not Lower Coverage
This project enforces coverage thresholds via Vitest (v8 provider). Any new .ts file you add to src/ that is not excluded must be accompanied by tests so the overall coverage does not regress.
Thresholds (from vitest.config.ts)
| Metric | Minimum |
|---|---|
| Statements | 90 % |
| Lines | 90 % |
| Functions | 90 % |
| Branches | 85 % |
Rules
- New source file → new test file. Every file added under
src/(exceptsrc/generated/**,src/tests/**,src/toon-demo.ts) must have a corresponding test undersrc/tests/that exercises its public API. - Mirror the source tree. Place test files at
src/tests/<subpath>/<module>.test.tsto mirrorsrc/<subpath>/<module>.ts. - Verify locally before committing. Run
npm run test:coverageand confirm the summary still meets all four thresholds. A red threshold line is a hard blocker. - No untested exports. Every exported function, class, and constant must appear in at least one
it()/test()block. Stubs andvi.fn()mocks count only toward the caller's coverage, not the callee's. - Branches need cases. For every
if/switch/ternary in new code, write at least one test for the truthy path and one for the falsy path. - Do not widen the coverage exclusion list. Adding a new glob to
vitest.config.ts → coverage.excludeto hide a file from reporting is not an acceptable workaround.
Workflow
1. Write (or modify) src/<path>/<module>.ts
2. Create src/tests/<path>/<module>.test.ts
3. npm run test:coverage
4. Confirm thresholds pass — fix gaps before opening a PR
Quick check (coverage summary)
# Show per-file coverage for the file you just added
npx vitest run --coverage --reporter=text 2>&1 | grep "<module>"
Anti-patterns
- Adding a new utility module with zero tests "to keep the PR small"
- Relying on integration tests in another file to cover a new module
- Deleting tests to make a failing threshold pass
- Using
/* c8 ignore next */to skip coverage on non-trivial logic
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.
- 8d ago First seen · 49 lines · 605 tokens per session scan A e1b0136eebd1
mcp-ai-agent-guidelines coverage-guard.instructions.md is an instructions file published in the GitHub repository Anselmoo/mcp-ai-agent-guidelines (6 stars, last pushed 3d ago), licensed MIT. It adds 605 tokens to every session, about $0.0030 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 2026-08-31.
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