Borrowing it
Nothing to install: this file belongs to harness/mcp-server. 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/harness/mcp-server/main/AGENTS.mdgit clone --depth 1 https://github.com/harness/mcp-serverWrote 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/harness/mcp-server/agents-md)<a href="https://agentmods.dev/instructions/harness/mcp-server/agents-md"><img src="https://agentmods.dev/badge/instructions/harness/mcp-server/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/harness/mcp-server/agents-md"><img src="https://agentmods.dev/badge/instructions/harness/mcp-server/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 | $0.02200 | $0.02200 |
| Opus 5.5 | $0.00880 | $0.00880 |
| Sonnet 5.5 | $0.00440 | $0.00440 |
| Haiku 4.5 | $0.00220 | $0.00220 |
Grade A, and why
mcp-server 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 — 175 lines — stays where its author put it; the contents beside it link to each section on GitHub.
AGENTS.md — Harness.io MCP Server
Registry-based MCP server: 11 consolidated tools (harness_list, harness_get, harness_create, harness_update, harness_delete, harness_execute, harness_search, harness_describe, harness_diagnose, harness_status, harness_schema) dispatching across 219+ resource types. TypeScript (Node.js 20+), ESM, pnpm, Zod v4.
Commands
pnpm install # install deps
pnpm build # tsc → build/
pnpm dev # tsc --watch
pnpm typecheck # tsc --noEmit
pnpm test # vitest run (118 test files, 2510 tests, ~9s)
pnpm standards:check # run coding-standards and structural validation tests
pnpm start # stdio transport (requires HARNESS_API_KEY)
pnpm start:http # HTTP transport (node build/index.js http)
pnpm inspect # MCP Inspector against stdio build
pnpm docs:generate # generate docs from build/ — run pnpm build first
pnpm docs:check # CI check (reads build/); stale build = wrong count and CI fail
Project Structure
src/
├── index.ts # Entrypoint — stdio/HTTP transport setup
├── config.ts # Env var validation (Zod); see .env.example for all vars
├── registry/
│ ├── index.ts # Core dispatch (~50K) — ResourceDefinition, EndpointSpec
│ ├── types.ts # Registry types: ResourceDefinition, EndpointSpec, OperationPolicy
│ ├── extractors.ts # Response shape extractors for all resource types
│ ├── scope-utils.ts # Scope resolution utilities
│ └── toolsets/ # 45 declarative toolset definition files (pure data — add new resources here)
├── tools/ # 11 consolidated tool handlers
├── prompts/ # ~33 prompt templates (one per workflow)
├── resources/ # MCP resources (pipeline YAML, execution summary)
├── client/
│ └── harness-client.ts # HTTP client — auth, retry, pagination
├── data/ # Example data and JSON schemas for entity validation
├── search/ # Cross-resource keyword search
├── audit/ # Audit manager
└── utils/ # Errors, logger, elicitation, deep-links, body normalizer
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 Changed · +10 tokens per session 5494d8728424
- 5d ago Changed · +4 lines · +85 tokens per session 9f7e88dbf2c1
- 28d ago Changed · +8 lines · +108 tokens per session 9f0e06e1043b
- 1mo ago Changed c1180e755af8
- 1mo ago Changed · +1 lines · +55 tokens per session 9a6ef60bc458
- 1mo ago First seen · 162 lines · 1,942 tokens per session scan A f85d0feb36c6
mcp-server AGENTS.md is an instructions file published in the GitHub repository harness/mcp-server (111 stars, last pushed yesterday), licensed MIT. It adds 2,200 tokens to every session, about $0.0088 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.
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).
vscode model-prompts.instructions.md
Model-specific prompt authoring and registry guidelines.