Mirror of https://github.com/modelcontextprotocol/servers — Model Context Protocol Servers
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  • Python 16.9%
  • JavaScript 10.4%
  • Dockerfile 1%
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Filename Latest commit message Latest commit date
Cliff Hall 25e5f3a6e8
fix(everything): prevent URL elicitation error-path infinite loop (#4285)
* url elicitation

* single tool for normal and error path

* Address review feedback on URL elicitation tool

- Remove src/everything/pnpm-lock.yaml (monorepo uses npm workspaces)
- Drop redundant TriggerUrlElicitationSchema.parse(args) in the handler;
  destructure directly from args like the other tools, since the SDK
  validates against the registered schema before invoking the handler
- Add explicit accept/decline/cancel messaging in the request path,
  mirroring trigger-elicitation-request.ts
- Clarify the registerTool count comment in registrations.test.ts
  (task-based tools register via registerToolTask, counted separately)
- Add tests covering the no-url / undefined-capability registration
  guards, the randomUUID() elicitationId fallback, and the
  decline/cancel response paths (100% coverage of the tool)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* Add tool annotations to trigger-url-elicitation

Match the annotations block on sibling elicitation tools and the
CLAUDE.md guidance. Uses openWorldHint: true since the tool drives an
external browser flow.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix(everything): prevent URL elicitation error-path infinite loop

The trigger-url-elicitation tool's error path (errorPath=true) threw
UrlElicitationRequiredError (-32042) carrying the same URL that failed and
re-threw it on every retry, so clients looped (and tripped their own loop
detection).

- Point the prerequisite elicitation at a different URL
  (https://modelcontextprotocol.io) than the failing request.
- Track issued prerequisites by the inputs a client resends on retry
  (session + url + caller-supplied elicitationId); a plain retry is then
  recognized, ignores errorPath, and proceeds via the request path instead
  of re-throwing the prerequisite.
- Update tests and docs accordingly.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix(everything): address review on URL elicitation error path

- Replace raw NUL byte delimiters in errorPathKey with the \u0000 escape
  sequence so the source stays plain text and the diff is reviewable
  (same collision-proof delimiter at runtime).
- Add a one-shot test reset helper + beforeEach so the suite is robust to
  the module-level marker state regardless of order.
- Use a dedicated prerequisite message instead of reusing the caller's.
- Document the unbounded-growth tradeoff as a demo simplification and note
  the one-shot marker semantics in docs/features.md.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: evalstate <1936278+evalstate@users.noreply.github.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-06 18:47:20 -07:00
.github docs: retire third-party server list in favor of MCP Registry 2026-04-14 08:05:23 -07:00
scripts fix: use --frozen instead of --locked in release workflow (#3140) 2025-12-18 16:25:49 +00:00
src fix(everything): prevent URL elicitation error-path infinite loop (#4285) 2026-06-06 18:47:20 -07:00
.gitattributes Initial commit 2024-11-19 13:29:12 +00:00
.gitignore Ignore the .vscode folder 2025-12-06 15:29:46 +01:00
.mcp.json Add MCP docs server to Claude Code GitHub Action 2025-11-26 07:47:50 -07:00
.npmrc Initial commit 2024-11-19 13:29:12 +00:00
ADDITIONAL.md Move a list of frameworks and resources to a separate md file to make README more readable and lightweight (#4255) 2026-05-30 09:44:47 -07:00
CLAUDE.md docs: add root CLAUDE.md and fix AGENTS.md typo 2026-03-27 14:37:53 +01:00
CODE_OF_CONDUCT.md Initial commit 2024-11-19 13:29:12 +00:00
CONTRIBUTING.md docs: retire third-party server list in favor of MCP Registry 2026-04-14 08:05:23 -07:00
LICENSE chore: update licensing to Apache 2.0 for new contributions 2026-01-12 22:50:22 +00:00
package-lock.json chore(deps): npm audit fix for high/medium security alerts 2026-05-16 08:54:35 -07:00
package.json chore: update licensing to Apache 2.0 for new contributions 2026-01-12 22:50:22 +00:00
README.md Move a list of frameworks and resources to a separate md file to make README more readable and lightweight (#4255) 2026-05-30 09:44:47 -07:00
SECURITY.md Update SECURITY.md to use GitHub Security Advisories 2026-02-18 20:51:23 +00:00
tsconfig.json Create package for each server 2024-11-19 14:26:59 +00:00

Model Context Protocol servers

This repository is a collection of reference implementations for the Model Context Protocol (MCP), as well as references to community-built servers and additional resources.

Important

If you are looking for a list of MCP servers, you can browse published servers on the MCP Registry. The repository served by this README is dedicated to housing just the small number of reference servers maintained by the MCP steering group.

Warning

The servers in this repository are intended as reference implementations to demonstrate MCP features and SDK usage. They are meant to serve as educational examples for developers building their own MCP servers, not as production-ready solutions. Developers should evaluate their own security requirements and implement appropriate safeguards based on their specific threat model and use case.

The servers in this repository showcase the versatility and extensibility of MCP, demonstrating how it can be used to give Large Language Models (LLMs) secure, controlled access to tools and data sources. Typically, each MCP server is implemented with an MCP SDK:

🌟 Reference Servers

These servers aim to demonstrate MCP features and the official SDKs.

  • Everything - Reference / test server with prompts, resources, and tools.
  • Fetch - Web content fetching and conversion for efficient LLM usage.
  • Filesystem - Secure file operations with configurable access controls.
  • Git - Tools to read, search, and manipulate Git repositories.
  • Memory - Knowledge graph-based persistent memory system.
  • Sequential Thinking - Dynamic and reflective problem-solving through thought sequences.
  • Time - Time and timezone conversion capabilities.

Archived

The following reference servers are now archived and can be found at servers-archived.

  • AWS KB Retrieval - Retrieval from AWS Knowledge Base using Bedrock Agent Runtime.
  • Brave Search - Web and local search using Brave's Search API. Has been replaced by the official server.
  • EverArt - AI image generation using various models.
  • GitHub - Repository management, file operations, and GitHub API integration.
  • GitLab - GitLab API, enabling project management.
  • Google Drive - File access and search capabilities for Google Drive.
  • Google Maps - Location services, directions, and place details.
  • PostgreSQL - Read-only database access with schema inspection.
  • Puppeteer - Browser automation and web scraping.
  • Redis - Interact with Redis key-value stores.
  • Sentry - Retrieving and analyzing issues from Sentry.io.
  • Slack - Channel management and messaging capabilities. Now maintained by Zencoder
  • SQLite - Database interaction and business intelligence capabilities.

🚀 Getting Started

Using MCP Servers in this Repository

TypeScript-based servers in this repository can be used directly with npx.

For example, this will start the Memory server:

npx -y @modelcontextprotocol/server-memory

Python-based servers in this repository can be used directly with uvx or pip. uvx is recommended for ease of use and setup.

For example, this will start the Git server:

# With uvx
uvx mcp-server-git

# With pip
pip install mcp-server-git
python -m mcp_server_git

Follow these instructions to install uv / uvx and these to install pip.

Using an MCP Client

However, running a server on its own isn't very useful, and should instead be configured into an MCP client. For example, here's the Claude Desktop configuration to use the above server:

{
  "mcpServers": {
    "memory": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-memory"]
    }
  }
}

On Windows, wrap npx with cmd /c:

{
  "mcpServers": {
    "memory": {
      "command": "cmd",
      "args": ["/c", "npx", "-y", "@modelcontextprotocol/server-memory"]
    }
  }
}

Additional examples of using the Claude Desktop as an MCP client might look like:

{
  "mcpServers": {
    "filesystem": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-filesystem", "/path/to/allowed/files"]
    },
    "git": {
      "command": "uvx",
      "args": ["mcp-server-git", "--repository", "path/to/git/repo"]
    },
    "github": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-github"],
      "env": {
        "GITHUB_PERSONAL_ACCESS_TOKEN": "<YOUR_TOKEN>"
      }
    },
    "postgres": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-postgres", "postgresql://localhost/mydb"]
    }
  }
}

On Windows, apply the same wrapper to each npx-based entry above by changing "command" to "cmd" and prepending "/c", "npx" to the existing args. Leave uvx entries unchanged.

🛠️ Creating Your Own Server

Interested in creating your own MCP server? Visit the official documentation at modelcontextprotocol.io for comprehensive guides, best practices, and technical details on implementing MCP servers.

📚 Learn More

See ADDITIONAL.md for a curated list of frameworks and resources that simplify building MCP servers and clients.

🤝 Contributing

See CONTRIBUTING.md for information about contributing to this repository.

🔒 Security

See SECURITY.md for reporting security vulnerabilities.

📜 License

This project is licensed under the Apache License, Version 2.0 for new contributions, with existing code under MIT - see the LICENSE file for details.

💬 Community

⭐ Support

If you find MCP servers useful, please consider starring the repository and contributing new servers or improvements!


Managed by Anthropic, but built together with the community. The Model Context Protocol is open source and we encourage everyone to contribute their own servers and improvements!