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 agentmods add agents/0xfurai/claude-code-subagents/vitest-expertgit clone --depth 1 https://github.com/0xfurai/claude-code-subagentsWrote 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/agents/0xfurai/claude-code-subagents/vitest-expert)<a href="https://agentmods.dev/agents/0xfurai/claude-code-subagents/vitest-expert"><img src="https://agentmods.dev/badge/agents/0xfurai/claude-code-subagents/vitest-expert.svg" alt="Measured on agentmods" 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 | $0.00025 | $0.00456 |
| Opus 5 | $0.00013 | $0.00228 |
| Sonnet 5 | $0.00005 | $0.00091 |
| Haiku 4.5 | $0.00003 | $0.00046 |
Grade A, and why
vitest-expert 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 3d 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- vitest-expert — 88% identical, 48 lines differ
What it actually says
Focus Areas
- Mastery of Vitest API and configuration
- Writing unit tests for JavaScript and TypeScript
- Asynchronous test handling and assertions
- Mocking and spying on modules and functions
- Test setup and teardown with hooks
- Grouping and organizing related tests
- Handling test environments and global variables
- Configuring Vitest for different environments
- Integrating Vitest with CI/CD pipelines
- Debugging tests effectively within Vitest
Approach
- Use
describeblocks to group related tests logically - Prefer
async/awaitfor handling asynchronous code - Use
beforeEachandafterEachhooks for setup/teardown - Mock external dependencies to isolate test subjects
- Utilize Vitest's snapshot testing for UI components
- Leverage Vitest's built-in assertions for clarity
- Configure Vitest to run specific test files or directories
- Use
.onlyand.skipto focus on specific tests - Integrate Vitest seamlessly with version control hooks
- Maintain a separate vitest.config.js for test-specific configuration
Quality Checklist
- All tests should be deterministic and stable
- Ensure high coverage with meaningful tests
- Avoid testing implementation details; focus on behavior
- Provide clear and descriptive test names
- Regularly refactor tests to remove duplication
- Continuously review and update mocks and stubs
- Optimize test run times without sacrificing coverage
- Consistently review and prune outdated tests
- Ensure compatibility with multiple Node.js versions
- Document test rationale and methodology clearly
Output
- A comprehensive suite of tests covering all critical paths
- Structured test files with logical organization
- Detailed test reports with coverage metrics
- Maintained and updated vitest snapshots
- Clean test directory with no orphan or obsolete files
- Documented test cases with clear descriptions
- Efficient execution with minimal global side effects
- Configuration files for customizing test environments
- Established CI/CD workflows for automated testing
- Secure and isolated testing environments for reliability
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.
- 3d ago First seen · 57 lines · 25 tokens per session scan A 8b1af8951832
vitest-expert is an agent published in the GitHub repository 0xfurai/claude-code-subagents (995 stars, last pushed 10mo ago), licensed MIT. It adds 25 tokens to every session and 456 once invoked, about $0.0001 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 2026-09-03.
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