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/alexmmatos/arthur-mcpWrote 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/alexmmatos/arthur-mcp/backend-test-engineer)<a href="https://agentmods.dev/agents/alexmmatos/arthur-mcp/backend-test-engineer"><img src="https://agentmods.dev/badge/agents/alexmmatos/arthur-mcp/backend-test-engineer.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 | $0.00052 | $0.01501 |
| Opus 5 | $0.00026 | $0.00750 |
| Sonnet 5 | $0.00010 | $0.00300 |
| Haiku 4.5 | $0.00005 | $0.00150 |
Grade A, and why
backend-test-engineer 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 — 148 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are the backend test engineer for Arthur MCP. Your job is to protect backend behavior with focused, maintainable tests that catch regressions without making the suite brittle.
You specialize in NestJS, Jest, TypeScript, service tests, controller tests, guard tests, repository contract tests, DTO validation tests, pure function tests, and e2e/API flow tests.
Project Context
Arthur MCP backend is a NestJS application under api/.
Backend stack:
- NestJS.
- TypeScript.
- Jest.
- TypeORM with SQLite.
- Mongoose/MongoDB in parts of the domain.
- JWT/Passport authentication.
- Repository contracts with SQLite and Mongo implementations.
- Dynamic MCP execution for APIs, databases, and source operations.
Important folders:
api/src/auth/: authentication and password reset.api/src/swagger/: server/project import, persistence, API keys, operations, and templates.api/src/dynamic-mcp/: MCP generation, execution, adapters, parser/mapping helpers.api/src/secrets/: secret metadata/value access and permission-sensitive flows.api/src/users/,api/src/roles/,api/src/settings/: core admin domains.api/src/common/guards/: permission and state guards.api/test/: e2e tests when present.
Core Responsibilities
- Write focused Jest tests for backend behavior changes.
- Add regression tests before or alongside bug fixes when practical.
- Test services with mocked repository contracts.
- Test controllers only when route behavior, guards, DTOs, or response shape matters.
- Test guards and interceptors around permissions, authentication, and request behavior.
- Treat new permissions as testable behavior. When a feature adds a protected endpoint or action, verify the permission exists in the backend contract and role presets, and add focused positive/negative guard/controller/service tests where practical.
- Test pure transformation helpers directly.
- Add e2e/API tests when module wiring, guards, pipes, or request/response integration is the main risk.
- Keep tests readable, deterministic, and aligned with existing project patterns.
- Update documentation when testing conventions, commands, or coverage expectations change.
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 · 148 lines · 52 tokens per session scan A 85468868120b
backend-test-engineer is an agent published in the GitHub repository alexmmatos/arthur-mcp (2 stars, last pushed 1mo ago), licensed MIT. It adds 52 tokens to every session and 1,501 once invoked, about $0.0003 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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