Borrowing it
Nothing to install: this file belongs to gaffer-sh/mcp. 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/gaffer-sh/mcp/main/AGENTS.mdgit clone --depth 1 https://github.com/gaffer-sh/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/gaffer-sh/mcp/agents-md)<a href="https://agentmods.dev/instructions/gaffer-sh/mcp/agents-md"><img src="https://agentmods.dev/badge/instructions/gaffer-sh/mcp/agents-md/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/gaffer-sh/mcp/agents-md"><img src="https://agentmods.dev/badge/instructions/gaffer-sh/mcp/agents-md.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 | $0.00615 | $0.00615 |
| Opus 5.5 | $0.00246 | $0.00246 |
| Sonnet 5.5 | $0.00123 | $0.00123 |
| Haiku 4.5 | $0.00061 | $0.00061 |
Grade A, and why
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 2mo 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 — 51 lines — stays where its author put it; the contents beside it link to each section on GitHub.
AGENTS.md
MCP server for Gaffer. TypeScript, built with tsdown, published to npm as @gaffer-sh/mcp.
Architecture
This server is an external API consumer. It calls Gaffer's public /api/v1/ endpoints over HTTP like any third-party client, and never bypasses the public API. If an endpoint does not support what a function needs, the fix belongs in the API, not here.
The server runs in code mode: three MCP tools plus a codemode namespace of 16 functions that execute_code calls from sandboxed JavaScript. That keeps 16 tool definitions out of the client's context window and lets one execution chain several calls.
| Path | What it holds |
|---|---|
src/index.ts |
MCP server, the three tool registrations, stdio transport |
src/codemode/ |
Registry, executor, type generation, keyword search |
src/tools/ |
One file per function: inputSchema, execute, metadata |
src/api-client.ts |
HTTP client for the Gaffer API |
src/types.ts |
Shared types |
Commands
pnpm install
pnpm build # tsdown, then chmod +x dist/index.js
pnpm test # vitest
pnpm typecheck
Adding a function
- Create
src/tools/<name>.tsmatching the existing shape. - Add an API client method if needed.
- Register it in
src/codemode/register-tools.tswith a category and keywords. - Add it to the function table in
README.md.
Step 4 is enforced: src/codemode/__tests__/docs-sync.test.ts fails if a registered function is undocumented. The README is what npm and every MCP directory scrape, so it drifting is a distribution problem, not a docs nit.
Functions go in the codemode registry, not in the MCP tool list. Only add a first-class MCP tool when a client needs it before any code executes.
Environment
| Variable | Required | Description |
|---|---|---|
GAFFER_API_KEY |
Yes | gaf_ user key or gfr_ project token |
GAFFER_API_URL |
No | Defaults to https://app.gaffer.sh |
gaf_ keys read across projects and enable list_projects. gfr_ tokens are scoped to one project, and projectId resolves automatically, so callers must omit it.
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.
- 2mo ago First seen · 51 lines · 615 tokens per session scan A 0648f27e688f
mcp AGENTS.md is an instructions file published in the GitHub repository gaffer-sh/mcp (1 stars, last pushed 2mo ago), licensed MIT. It adds 615 tokens to every session, about $0.0025 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 2026-08-31.
Other instructions, from other repositories
vscode buildNext.instructions.md
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).
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.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, cache eligibility and rollout and applying the notice (cutover).
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 copilot-instructions.md
Copilot instructions for microsoft/vscode, covering vs code copilot instructions, project overview, root folders, core architecture (src/ folder) and built-in extensions (extensions/ folder).
deno copilot-instructions.md
Copilot instructions for denoland/deno, covering deno development guide for github copilot, network access, high level overview, key directories and key files to understand first.