BRYDGE MCP server

brydge-mcp

Check whether your agent's work actually happened.

This is BRYDGE as an MCP server. Before an agent acts, BRYDGE decides whether it may. Afterwards, BRYDGE reads the destination system's own records, such as your payment processor or ticket system, using its own credential. It then reports whether the work happened as permitted. What the agent says happened is kept beside that finding and never decides it.

Tools

The server also gives the model its instructions: ask first, cite the authorization, report, then verify before saying the work is done.

Set up BRYDGE first

Do these once, in BRYDGE:

1. Issue an API key on the Connect page.
2. Declare what the action is worth. BRYDGE charges a share of that value, and it will not check an action nobody has priced.
3. Register a destination for the action: where BRYDGE reads the records, and the read-only credential it uses. BRYDGE has a preset for Stripe refunds.
4. Issue a mandate to the agent for the action. Without one, every call goes to a person.

A mandate says what the agent may do; headroom says how much of it, in any 24 hours. A new agent starts with room for one action a day, and every report BRYDGE checks and finds true raises that.

Add it to your MCP client

Most clients take this configuration (Claude Desktop, Cursor, Windsurf and others):

{
  "mcpServers": {
    "brydge": {
      "command": "npx",
      "args": ["-y", "brydge-mcp"],
      "env": {
        "BRYDGE_API_KEY": "brydge_sk_...",
        "BRYDGE_ACTOR": "agent:refund-ops"
      }
    }
  }
}

On Windows, npx is a .cmd file, and only clients that start commands through a shell or through the MCP SDK can launch it by name. If your client reports spawn npx ENOENT, start it through the command shell instead:

{
  "mcpServers": {
    "brydge": {
      "command": "cmd",
      "args": ["/c", "npx", "-y", "brydge-mcp"],
      "env": {
        "BRYDGE_API_KEY": "brydge_sk_...",
        "BRYDGE_ACTOR": "agent:refund-ops"
      }
    }
  }
}

In Claude Code:

claude mcp add brydge -e BRYDGE_API_KEY=brydge_sk_... -e BRYDGE_ACTOR=agent:refund-ops -- npx -y brydge-mcp

The agent's name comes from this configuration, never from the model, so an agent cannot borrow another agent's permissions. Run one server per agent.

How an agent uses it

1. Ask first. Before a refund, payment or other change, the agent calls brydge_supervise with the action, the target and the facts, such as {"amount": 4200}.
2. Cite the authorization. If the answer is ALLOWED, the agent carries the action out and writes the authorization id where the destination keeps it. For a Stripe refund, that is metadata.brydge_authorization. BRYDGE finds the work by this id, and by nothing else.
3. Report. The agent calls brydgereportoutcome with what it believes happened.
4. Verify. Before saying the work is done, the agent calls brydge_verify.

Shortened. The full README is on GitHub.