Skip to main content
The Numeral MCP server is a single HTTPS endpoint that exposes your Numeral account — nexus, filings, registrations, transactions, sales, products, and exemption certificates — as tools an AI agent can call directly.
It speaks Model Context Protocol, so any MCP-capable client (Claude Code, Claude Desktop, Cursor, or your own agent built on an LLM SDK) can connect with your existing Numeral secret API key and start answering questions like “which states have I triggered nexus in, and are any filings waiting on my review?”

Quickstart

Connect a client and make your first call in a few minutes.

Tool reference

Every tool the server exposes, with its inputs.

Authentication & limits

Keys, testmode, tenancy, rate limits, and error codes.

Demo application

A complete public example app you can run locally.

​
Why use the MCP instead of the REST API

The REST API is the right tool when you are writing code with a fixed, known shape — a checkout that calculates tax, a job that commits transactions. You decide at build time which endpoints to call. The MCP server is the right tool when an agent decides at runtime what to look up. Because the server describes itself, your agent needs no Numeral-specific integration code:
  • tools/list replaces API documentation. Every tool arrives with a description and a JSON Schema for its inputs. The agent reads the catalog and knows how to call each tool.
  • New capabilities appear automatically. When Numeral ships a new tool, it shows up in tools/list on your next request and your agent can use it immediately — no SDK upgrade, no redeploy.
  • Errors are written for agents. Failed calls return a stable, machine-readable error_code so the agent can correct itself and retry rather than giving up.
Both surfaces are backed by the same data and the same API keys, and you can use them together. Numeral has more than one thing with “MCP” in the name. They do different jobs: This section of the docs covers the first one.

​
What the tools cover

All tools operate on the account your API key belongs to. There is no account parameter, so a request cannot reach another tenant’s data. See the tool reference for exact names and inputs.
The tools available today are read-only — no tool changes your data. Write capabilities are gated per account; see write tools for details.

​
How it works

The server is a stateless Streamable HTTP endpoint. Every request is a JSON-RPC 2.0 POST carrying your API key, authenticated on its own — there is no session to establish or maintain, and no state is retained between calls. Three JSON-RPC methods matter: Most MCP clients handle all three for you — you supply a URL and a key. If you are building your own agent, the demo application shows the full loop in about 150 lines. There is also a GET /ping health check that returns {"status":"ok"}.

​
Next step

Connect a client

Point Claude Code, Claude Desktop, or Cursor at the server and ask your first question.