@exhibita/mcp

Turn an MCP server's tool calls into ExhibitA agent events with near-zero integration. Wrap your toolset once and every call an agent makes becomes signed, schema-valid evidence — no per-tool plumbing.

import { createSensor, instrumentServer } from "@exhibita/mcp";

const sensor = createSensor({
  apiKey: process.env.EXHIBITA_API_KEY!,
  signingKey: process.env.EXHIBITA_SIGNING_KEY!,
  signingKeyId: process.env.EXHIBITA_SIGNING_KEY_ID!,
});

// Wrap your whole toolset. The returned handlers are drop-in replacements:
// same signatures, same return values, same thrown errors — now recorded.
const tools = instrumentServer(
  sensor,
  {
    search_catalog: async (q: string) => db.search(q),
    checkout: async (cart: Cart) => payments.charge(cart),
  },
  // Optional: you own the clock. Called once per invocation.
  { now: () => new Date().toISOString() },
);

// Register `tools` with your MCP server exactly as before.

Event type is inferred from each call:

• agent.api_call — normal tool
• agent.checkout_completed / agent.checkout_failed — tool name implies checkout/payment, on success / failure
• agent.blocked — upstream returned status 403 or 429

Need lower-level control? wrapTool(sensor, name, handler, opts?) wraps a single handler, and recordToolCall(sensor, info) emits an event directly.