Mercur
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Remote MCP

Remote MCP lets an AI agent in your editor inspect HTTP request history, WebSocket connections, and inbound mail on your Mercur workspace. Connect with OAuth (URL only) or a workspace API key — no local install and no npm package.

Use it when you are debugging webhooks or mailbox deliveries and want the agent to list recent items, open a failed delivery, and read the payload that actually arrived.

1. Add Mercur to your MCP client (OAuth)

Paste this as a remote / HTTP MCP server. Your client opens a browser; sign in and pick a Solo or Team workspace.

{
  "mcpServers": {
    "mercur": {
      "url": "https://console.mercur.sh/api/mcp"
    }
  }
}

On localhost, use your console origin instead of https://console.mercur.sh.

Works with Cursor, Claude Desktop, and other clients that support remote MCP over HTTP and OAuth.

Open Workspace Settings

2. Optional: workspace API key

If your client cannot run OAuth, create a key under Settings → Workspace → API keys and paste a snippet with Authorization: Bearer mcr_…. Any workspace member can create or revoke keys. Copy the secret immediately — Mercur shows the full token once.

Revoke OAuth grants under Settings → Workspace → Connected MCP clients.

3. Ask the agent to inspect traffic

Once the server is connected, ask the agent to list your tunnels or mailboxes and inspect recent traffic — for example a failed webhook or an inbound test email.

The agent can only see endpoints, logs, and mail in the workspace that owns the grant or API key.

Tools

Mercur exposes read-only tools:

  • list_endpoints — list HTTP endpoints in the workspace
  • list_requests — browse request history as summaries (method, path, status, timing). No bodies or headers in the list. Optional filters: path, method, status, session, time range, and pagination
  • get_request — open one request in full, including headers and bodies
  • list_connections — browse WebSocket connection history as summaries (path, state, timing). No handshake headers or payloads. Optional filters: path, state, pagination
  • get_connection — open one connection’s handshake (headers, close). No frame payloads
  • list_connection_events — browse lifecycle and message events as summaries. No payloads. Pagination only
  • get_connection_event — open one event in full, including the stored payload
  • list_mailboxes — list temporary @mercur-mail.com inboxes (id, address, name)
  • list_messages — browse inbound mail as summaries (from, subject, date). No bodies or headers in the list. Pagination only
  • get_message — open one message in full (headers, text, html, attachment metadata). No raw MIME or file bytes

Typical HTTP flow: list_endpoints → list_requests → get_request.

Typical WebSocket flow: list_endpoints → list_connections → list_connection_events → get_connection_event.

Typical mail flow: list_mailboxes → list_messages → get_message.

Revoking access

Disconnect an OAuth client from Settings → Workspace → Connected MCP clients, or revoke an API key from API keys. The client stops working with that token immediately.

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