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 instructions/arr-mcps/lidarr-mcp/agents-mdgit clone --depth 1 https://github.com/arr-mcps/lidarr-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/instructions/arr-mcps/lidarr-mcp/agents-md)<a href="https://agentmods.dev/instructions/arr-mcps/lidarr-mcp/agents-md"><img src="https://agentmods.dev/badge/instructions/arr-mcps/lidarr-mcp/agents-md.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 | $0.01633 | $0.01633 |
| Opus 5 | $0.00816 | $0.00816 |
| Sonnet 5 | $0.00327 | $0.00327 |
| Haiku 4.5 | $0.00163 | $0.00163 |
Grade A, and why
lidarr-mcp AGENTS.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 4d 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 — 60 lines — stays where its author put it; the contents beside it link to each section on GitHub.
AGENTS.md — lidarr-mcp
MCP server exposing Lidarr's v1 REST API (OpenAPI 3.0.4) as tools so an LLM can read and manage a Lidarr instance: artists, albums, tracks, track files, queue, wanted, history, indexers, import lists, metadata profiles, custom formats, tags, commands, system status, and more. Full surface — reads and writes. Uses FastMCP, uv for deps.
Exposed as 15 resource-scoped portmanteau tools, not one tool per endpoint — see "Tool registry and the spec" below. A one-tool-per-endpoint version of this API would register 221 endpoints individually, blowing the MCP context budget (~221 tools × ~250 tokens ≈ 55k tokens just for this one server); the grouped version costs roughly a tenth of that.
Testing
- Offline suite:
make test(oruv run pytest) - Live integration (needs
LIDARR_URL/LIDARR_API_KEY):make test-integration- GET endpoints run against the live instance.
- POST/PUT/DELETE only run when
LIDARR_WRITE_TESTS=1(safe create→update→delete cycles against a scratch tag, then cleanup). Never point write tests at a production library.
Tool registry and the spec
_TOOL_REGISTRYinlidarr_mcp.pyis generated from the vendored spec attests/data/lidarr_openapi.json(pinned to Lidarr develop HEAD d88cbcec050c04b3064c9f36221edac152e241e2). It lists every JSON-producing endpoint under/api/v1plusGET /ping.- Excluded on purpose:
/login,/logout, static web routes, the.icscalendar feed, and binary/text endpoints (media covers, raw log files) —_reqJSON-decodes every response./pingis kept. - To add a tool or refresh coverage, regenerate the registry from a newer
openapi.json(same algorithm as the authoring script) and re-run the tests. Do not hand-edit the registry. - Endpoint function naming (internal, no longer an MCP tool name):
lidarr_<verb>_<resource>derived from path + method (e.g.lidarr_list_artist,lidarr_add_album,lidarr_delete_trackfile,lidarr_run_command). Overrides for flagship/action endpoints live in the authoring script.
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.
- 4d ago First seen · 60 lines · 1,633 tokens per session scan A 2eeb7ffcd5c9
lidarr-mcp AGENTS.md is an instructions file published in the GitHub repository arr-mcps/lidarr-mcp (0 stars, last pushed 9d ago), licensed MIT. It adds 1,633 tokens to every session, about $0.0082 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.
Other instructions, from other repositories
codex AGENTS.md
AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.
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Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
spec-kit AGENTS.md
AGENTS.md instructions for github/spec-kit, covering agents.md, about spec kit and specify, quickstart — add a new integration in 5 steps, integration architecture and integrationmanifest — file tracking.
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, applying the notice (cutover) and fallback chain (never fail the build).