@rankigi/mcp

Cryptographically sealed records for every MCP tool call.

What it does

Every MCP tools/call request becomes a RANKIGI tool_call event. Every matching response becomes a tool_result event linked by the JSON-RPC id. Both are SHA-256 hashed, hash-chained to the previous event in the agent's ledger, and anchored to the Sigstore public transparency log. Neither event blocks execution. If RANKIGI is unreachable, your agent continues.

Server-side (recommended)

import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import { wrapMcpServer } from "@rankigi/mcp/server";

const server = new McpServer({ name: "my-server", version: "1.0.0" });
await server.connect(new StdioServerTransport());

wrapMcpServer(server, {
  apiKey: process.env.RANKIGI_API_KEY!,
  agentId: process.env.RANKIGI_AGENT_ID!,
  mcpServer: "my-server",
});

Client-side

import { Client } from "@modelcontextprotocol/sdk/client/index.js";
import { StdioClientTransport } from "@modelcontextprotocol/sdk/client/stdio.js";
import { wrapMcpTransport } from "@rankigi/mcp/client";

const transport = wrapMcpTransport(
  new StdioClientTransport({ command: "node", args: ["server.js"] }),
  {
    apiKey: process.env.RANKIGI_API_KEY!,
    agentId: process.env.RANKIGI_AGENT_ID!,
    mcpServer: "my-server",
  },
);

const client = new Client({ name: "my-client", version: "1.0.0" });
await client.connect(transport);

Event shape

tool_call event payload:

{
  "action": "tool_call",
  "payload": {
    "tool": "search_web",
    "input_hash": "9af1c8...",
    "input_size": 142,
    "mcp_request_id": 7,
    "mcp_server": "my-server",
    "mcp_protocol_version": "2.0"
  }
}

tool_result event payload:

{
  "action": "tool_result",
  "payload": {
    "tool": "search_web",
    "output_hash": "2c1e44...",
    "output_size": 8421,
    "mcp_request_id": 7,
    "mcp_server": "my-server",
    "duration_ms": 482,
    "is_error": false
  }
}

Two events, not one

tool_call and tool_result are emitted as separate chain events, linked by mcp_request_id. The temporal separation preserves the start-to-finish latency of each tool invocation as on-chain evidence and keeps the hash chain continuous during long tool runs. A single combined event would erase that latency record and would force the chain to stall for the duration of the tool call, which violates RANKIGI's non-blocking guarantee.

Installation

npm install @rankigi/mcp @rankigi/sdk @modelcontextprotocol/sdk

Environment variables

• RANKIGI_API_KEY: ingest API key from your RANKIGI dashboard
• RANKIGI_AGENT_ID: agent UUID from your RANKIGI dashboard

Notes

• Raw tool arguments and results are never transmitted. Only SHA-256 hashes and size in bytes leave the process.
• All RANKIGI calls are fire-and-forget with a 5 second timeout. They cannot throw into your tool handler.
• Optional onError callback receives any transport-layer failures for logging.