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/microsoft/mcp/agents-mdgit clone --depth 1 https://github.com/microsoft/mcpWhat 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 | $0.07571 | $0.07571 |
| Opus 5 | $0.03785 | $0.03785 |
| Sonnet 5 | $0.01514 | $0.01514 |
| Haiku 4.5 | $0.00757 | $0.00757 |
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 2d 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 — 786 lines — stays where its author put it; the contents beside it link to each section on GitHub.
AGENTS.md
Do
- Use primary constructors for all C# classes
- Use
System.Text.Json - Make command classes sealed unless designed for inheritance
- Make members static when possible for AOT compatibility
- Put each class and interface in separate files
- Use
subscriptionparameter (neversubscriptionId) - supports both IDs and names - Use
resourceGroup(notresourceGroupName) - Use singular nouns for resource names (e.g.,
server, notserverName) - Run
dotnet buildafter making changes - Follow the
{Resource}{Operation}Commandnaming pattern - Use the two-generic pattern
SubscriptionCommand<TOptions, TResult>for new commands - Use
[Option]attributes on flat POCO option classes for option declaration - Use
ISubscriptionOptioninterface on options classes that need subscription/tenant - Always call
HandleException(context, ex)in catch blocks - Include live tests for all commands that interact with Azure resources
- Create Bicep templates for Azure service commands (
test-resources.bicep) - Include post-deployment scripts (
test-resources-post.ps1) - Record all live tests according to the guidelines in
/docs/recorded-tests.md - Submit one tool per pull request
- Use
BaseAzureResourceServicefor Resource Graph queries when possible - Register all response models in JSON serialization context for AOT safety
- Register all commands in the appropriate Setup.cs file
- Use concatenated lowercase for command group names (no dashes)
- Prefer file-scoped changes over project-wide modifications when possible
- Always review your own code for consistency, maintainability, and testability
- Always ask for clarifications if the request is ambiguous or lacks sufficient context
- Write transport-agnostic commands that work in both stdio and HTTP modes
- Keep commands stateless and thread-safe for multi-user remote scenarios
- Test commands with different RBAC permissions for OBO scenarios
Don't
- Use
subscriptionIdparameter name - Add unnecessary "-name" suffixes (use
--accountvs--account-name) - Use the old one-generic
RegisterOptions/BindOptionspattern for new commands (see/docs/option-conversion.md) - Use
OptionDefinitionsstatic classes for new commands (use[Option]attributes instead) - Use options class inheritance hierarchies (use flat POCOs with interface constraints)
- Skip live tests, live test infrastructure, or test recordings for Azure service commands
- Redefine base class properties in Options classes
- Leave commands unregistered
- Skip error handling or comprehensive tests
- Use dashes in command group names (use concatenated lowercase)
- Make project-wide changes when file-scoped changes suffice
- Check transport type in commands (stdio vs HTTP)
- Store per-request state in command instance fields
- Access HttpContext directly from commands
- Make transport-specific decisions in command logic
- Assume single-user scenarios when implementing services
- Use
git stashin linked worktrees; the stash stack is shared across worktrees and can collide during concurrent work
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.
- 2d ago First seen · 786 lines · 7,571 tokens per session scan A f5328a2654a4
mcp AGENTS.md is an instructions file published in the GitHub repository microsoft/mcp (3,625 stars, last pushed 3d ago), licensed MIT. It adds 7,571 tokens to every session, about $0.0379 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 2026-08-30.
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.
buildNext
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
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, applying the notice (cutover) and fallback chain (never fail the build).
spec-kit 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.
langchain 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.