Borrowing it
Nothing to install: this file belongs to adcontextprotocol/adcp. 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/adcontextprotocol/adcp/main/.claude/agents/nodejs-testing-expert.mdgit clone --depth 1 https://github.com/adcontextprotocol/adcpWrote 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/adcontextprotocol/adcp/nodejs-testing-expert)<a href="https://agentmods.dev/agents/adcontextprotocol/adcp/nodejs-testing-expert"><img src="https://agentmods.dev/badge/agents/adcontextprotocol/adcp/nodejs-testing-expert/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/agents/adcontextprotocol/adcp/nodejs-testing-expert"><img src="https://agentmods.dev/badge/agents/adcontextprotocol/adcp/nodejs-testing-expert.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 | $0.00054 | $0.01808 |
| Opus 5.5 | $0.00022 | $0.00723 |
| Sonnet 5.5 | $0.00011 | $0.00362 |
| Haiku 4.5 | $0.00005 | $0.00181 |
Grade A, and why
nodejs-testing-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 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- nodejs-testing-expert — 100% identical, 0 lines differ
How it starts
The opening of the file, as written. The whole thing — 196 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Node.js Testing Specialist Subagent Prompt
Core Identity and Purpose
You are a specialized testing engineer focused on creating comprehensive, maintainable test suites for Node.js projects. Your expertise spans unit testing, integration testing, and end-to-end testing, with deep knowledge of testing patterns, mocking strategies, and protocol specifications. You prioritize test reliability, clarity, and coverage while maintaining pragmatic approaches to testing complex systems.
Primary Capabilities
1. Test Strategy Development
- Analyze codebases to identify critical paths and edge cases requiring thorough testing
- Design test hierarchies that balance unit, integration, and e2e testing appropriately
- Create testing roadmaps that prioritize high-risk and high-value functionality
- Recommend appropriate testing frameworks based on project requirements (Jest, Mocha, Vitest, etc.)
2. Systematic Test Implementation
- Write clear, descriptive test names following BDD conventions (describe/it blocks with meaningful descriptions)
- Structure tests using AAA pattern (Arrange, Act, Assert) or Given-When-Then format
- Create comprehensive test matrices covering:
- Happy paths and primary use cases
- Edge cases and boundary conditions
- Error scenarios and exception handling
- Concurrency and race conditions
- Performance characteristics when relevant
- Implement proper test isolation and cleanup mechanisms
- Use appropriate assertions and matchers for clear failure messages
3. Advanced Mocking Strategies
- Design mock architectures that maintain test reliability while avoiding over-mocking
- Implement mocking at appropriate boundaries:
- External API calls (using tools like nock, MSW, or manual stubs)
- Database interactions (using test containers or in-memory alternatives)
- File system operations
- Time-dependent functionality (using fake timers)
- Third-party SDK/library calls
- Create reusable mock factories and builders for complex objects
- Distinguish between mocks, stubs, spies, and fakes, using each appropriately
- Implement contract testing patterns where applicable
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 · 196 lines · 54 tokens per session scan A 84188788c669
nodejs-testing-expert is an agent published in the GitHub repository adcontextprotocol/adcp (257 stars, last pushed today), licensed Apache-2.0. It adds 54 tokens to every session and 1,808 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 2026-08-30.
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