Mercury MCP Server

Agent-payable web data over x402: 18 keyless services an agent pays per call.

Local serverstdio

What is the Mercury MCP server?

Connect Mercury to Claude, Cursor or any other MCP client and it stops being a tab you switch to. Agent-payable web data over x402: 18 keyless services an agent pays per call. The mercury mcp server is what makes that connection.

What the server does

Tools include: clean fetch, LLM-ready markdown, structured extract, link graph, robots, diff, notarize, headers, table extract, feed, availability, validate, batch, sitemap, DNS, readability, redirect — built live from Mercury's catalog, so the list is always current.

Credentials and setup notes

Configuration is passed through the environment: MERCURY_PRIVATE_KEY. Treat anything key-shaped as a real credential — scope it to the minimum the server needs, and rotate it if it ever lands in a shared config.

Installation

Installation goes through your MCP client rather than a global install: point it at mercury-x402-mcp on npm and it is fetched when the client starts. The copy-paste blocks for Claude Desktop, Claude Code and Cursor are further down this page.

Where it fits

This sits in the developer tooling group, where several servers overlap in what they claim to do but differ sharply once you actually set them up. It is maintained by mercuryx402; worth a glance at recent repository activity before you build anything load-bearing on it.

This entry was verified against Mercury's own documentation before publication; SyncDev keeps the directory reviewed rather than auto-generated.

Worth knowing first

  • It runs with your machine's permissions. That is convenient and also the reason to think about what you point it at before you approve a tool call.
  • Missing credentials fail quietly in some clients — if no tools show up, check the environment block first.
  • Keep per-call confirmation enabled while you learn its behaviour; it is the cheapest safeguard you have.

How to install the Mercury MCP server

{
  "mcpServers": {
    "mercury-x402": {
      "command": "npx",
      "args": ["-y", "mercury-x402-mcp"],
      "env": {
        "MERCURY_PRIVATE_KEY": "your-value"
      }
    }
  }
}

Add to claude_desktop_config.json, then restart Claude Desktop.

Configuration

VariableDescriptionRequired
MERCURY_PRIVATE_KEYCredential the server authenticates with.Yes

Frequently asked questions

It connects Mercury to MCP-compatible AI assistants such as Claude and Cursor. Instead of copying data back and forth by hand, the assistant works with Mercury directly.