mcp copilot-instructions.md

A set of coding and review rules for contributing to the microsoft/mcp repository, including C# style, testing, documentation, and pull-request practices.

In plain words
What is it for?
Use it while writing or reviewing C# and PowerShell changes, updating tests or documentation, and preparing pull requests for this repository.
Why use it?
It gives coding agents consistent project-specific instructions and helps changes meet the repository's build, security, and review requirements.

Instructions file for GitHub Copilot

Install

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.

agentmods
npx agentmods add instructions/microsoft/mcp/copilot-instructions
Clone the repo
git clone --depth 1 https://github.com/microsoft/mcp

Made for: GitHub Copilot.

Per session 1,122 This file is loaded in full into every session.
When invoked 1,122 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.01122 $0.01122
Opus 5 $0.00561 $0.00561
Sonnet 5 $0.00224 $0.00224
Haiku 4.5 $0.00112 $0.00112

Measured 2d ago against content hash 8457e627cf9a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

mcp copilot-instructions.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.

.github/copilot-instructions.md · 61 lines

How it starts

The opening of the file, as written. The whole thing — 61 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Coding Instructions for GitHub Copilot

  • Always use primary constructors in C#
  • Always run dotnet build after making a change
  • Always use System.Text.Json over Newtonsoft
  • Always put new classes and interfaces in separate files
  • Always make members static if they can be
  • All generated code needs to be AOT safe
  • Never expose RetryPolicyOptions through tool options or service contracts; use Azure SDK retry defaults
  • Always review your own code for consistency, maintainability, and testability
  • Always ask for clarifications if the request is ambiguous or lacks sufficient context.

Engineering System

  • Use ./eng/scripts/Build-Local.ps1 -VerifyNpx to verify changes to powershell, c# project files and npm packages
  • Don't run local builds to check pipeline YAML files (e.g., files in eng/pipelines/ with .yml extension)

Pull Request Guidelines

  • Ensure all tests pass
  • Follow the contribution guidelines
  • Include appropriate documentation
  • Include tests that cover your changes
  • Update CHANGELOG.md with your changes
  • Run .\eng\common\spelling\Invoke-Cspell.ps1
  • Create the auto-generated PR body as normal, but copilot should add an additional section after all of its regular PR body content. The contents should be:
    ## Invoking Livetests
    
    Copilot submitted PRs are not trustworthy by default. Users with `write` access to the repo need to validate the contents of this PR before leaving a comment with the text `/azp run mcp - pullrequest - live`. This will trigger the necessary livetest workflows to complete required validation.
    

Transitioning Live Tests to Recorded Tests

  • Always convert tool services to inject IHttpClientFactory into its clients and use IHttpClientFactory.CreateClient method to instantiate the HttpClient for usage in the tool classes' methods.
    • If IHttpClientFactory is already injected into the client, ensure that IHttpClientFactory.CreateClient is used to instantiate the HttpClient. If this is done, then no further action is needed.
  • Always re-parent test classes parented by CommandTestsBase to RecordedCommandTestsBase. This will require minor fixture adjustments.
  • Always generate a new assets.json file alongside the livetest csproj file if one does not exist. This file should contain the following content:
    {
      "AssetsRepo": "Azure/azure-sdk-assets",
      "AssetsRepoPrefixPath": "",
      "TagPrefix": "<TestCsProjFileNameWithoutExtension>", // e.g., "Azure.Mcp.Tools.KeyVault.Tests"
      "Tag": ""
    }
    
  • Copilot should utilize the recorded test documentation in docs/recorded-tests.md for more details on how to convert and validate recorded tests.

Read the full file on GitHub · 61 lines

Changes

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.

  1. 2d ago First seen · 61 lines · 1,122 tokens per session scan A 8457e627cf9a

Subscribe to this mod's changes

mcp copilot-instructions.md is an instructions file published in the GitHub repository microsoft/mcp (3,625 stars, last pushed 3d ago), licensed MIT. It adds 1,122 tokens to every session, about $0.0056 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.

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