Fetch MCP server (Rust, stdio)

A minimal, production-ready MCP server implemented in Rust using the rmcp crate and a stdio transport. It exposes a single safe HTTP GET tool you can call from MCP clients to fetch text from URLs, with optional timeout and response-size limits.

Why this repo?

• Clean, idiomatic Rust with async (Tokio) and a tiny surface area.
• Great starter template for building more MCP tools using rmcp macros.
• Safe-by-default: timeouts and max-bytes guardrails.

• RFetch tool: perform HTTP GET and return the response body as text
  • Optional timeout_secs (default 15s)
  • Optional max_bytes (default 1MB)
  • Follows up to 5 redirects
• Stdio transport: easy to wire into MCP-capable clients

Prerequisites: Rust toolchain (1.75+ recommended)

Build:

cargo build --release

Run (stdio):

cargo run --quiet

Install the binary to your Cargo bin directory (~/.cargo/bin by default):

cargo install --path .

Then run it directly (stdio server):

~/.cargo/bin/fetch_MCP_rust

Most MCP-capable clients can launch a stdio server by running a command. Use the installed binary path (e.g., ~/.cargo/bin/fetch_MCP_rust):

• Generic MCP client configuration (conceptual):

  • Command: ~/.cargo/bin/fetch_MCP_rust
  • Args: []

• Cursor (example): add an entry to your MCP servers configuration that runs the binary:

{
  "mcpServers": {
    "fetch-mcp": {
      "command": "~/.cargo/bin/fetch_MCP_rust",
      "args": []
    }
  }
}

Restart Cursor if needed so it discovers the server and the RFetch tool.

• Warp (example): open Warp AI, go to Tools (or MCP servers) and add a new server:
  • Command: ~/.cargo/bin/fetch_MCP_rust
  • Args: [] After adding, Warp should list the RFetch tool for use in the agent.

Tool name: RFetch Description: HTTP GET fetcher that returns response body as text

Parameters (JSON schema):

• url (string, required): The URL to fetch
• timeout_secs (integer, optional): Request timeout in seconds (default 15)
• max_bytes (integer, optional): Max bytes to return (default 1_000_000)

Example calls (from an MCP client):

{
  "name": "RFetch",
  "arguments": { "url": "https://example.com" }
}

{
  "name": "RFetch",
  "arguments": { "url": "https://example.com", "timeout_secs": 10, "max_bytes": 65536 }
}

1. Install and run the Inspector:

npx @modelcontextprotocol/inspector

2. In the Inspector, configure a stdio server that spawns this binary (path to your built executable). The server advertises the RFetch tool automatically.

This project uses rmcp macros — #[tool_router], #[tool], and #[tool_handler]. Add additional #[tool] functions to the FetchServer impl in src/main.rs to grow your toolset.

Issues and PRs are welcome. Please keep code idiomatic, documented, and tested. Consider adding examples and integration tests for new tools.

MIT or Apache-2.0 (match your preference for redistribution).