What it is and isn't

MCP (Model Context Protocol) is an open standard for an AI assistant (Claude Desktop, Claude Code, Cursor, or your own agent) to operate external tools in a structured way, instead of through free text. Nuntius has its own MCP server: it exposes your account — leads, contacts, conversations, appointments and tickets — as a set of tools your assistant can read and, with your confirmation, write to.

What it is

• A deterministic adapter, with no language model of its own: the LLM that decides which tool to call always lives in your client (Claude Desktop, Claude Code, Cursor…), never in this server.
• Exactly what the public API allows (/public/v1), not one endpoint more — its tools are generated by reading the same OpenAPI definition that documents the REST reference, so anything you can do over MCP you could also do with a direct curl call to the API. See the full tools catalog.
• No access to your database, nor to any data the API doesn’t already expose: every tool call forwards your own API key to /public/v1, as-is — the MCP server never stores your key and has no other path into your account. All control (permissions, plan, limits, isolation per account) is enforced by the API, not by this adapter.

What it isn’t

Don’t confuse this with the “external MCP servers” you can connect to your own AI agent from Settings → MCP servers (BYO-MCP) — they run the opposite direction:

	Nuntius’s MCP server (this section)	External MCP servers (BYO-MCP)
Direction	Exposes your Nuntius account to your external AI assistant	Plugs third-party tools into your account’s own AI agent
Who connects it	You, from your MCP client (Claude Desktop, Claude Code, Cursor…)	You, from the Platform, so the agent that serves your customers can use it
Where it’s configured	In your own MCP client’s configuration (see Connect your assistant)	In the Platform’s Settings → MCP servers

If what you’re after is giving your AI agent access to external tools (your CRM, your catalog, your calendar…), that’s the other piece — see the Settings & integrations guide, section 8. This section is about the opposite: giving your own AI assistant access to Nuntius.

Requirements

• Pro or Enterprise plan — on the Starter plan, every tool responds with the same 403 PLAN_NOT_ELIGIBLE the public API returns (see Plans and limits). The server always keeps listing the nuntius_status tool so your client can show a clear message about why nothing else is available.
• An API key with the scopes for the resources you want to use — the same mechanism, and the same screen, as the key you’d use to call /public/v1 directly (guide API keys, full scope catalog in Authentication). The tools your MCP client sees are exactly the ones your key can use — nothing more.

How it works, in three steps

Your MCP client (Claude Desktop / Claude Code / Cursor / your own agent)
      │  Streamable HTTP, header X-API-Key: <your key>
      ▼
Nuntius's MCP server  (no database, no state, no LLM of its own)
      │  forwards your same key, call by call
      ▼
Nuntius's public API  (/public/v1 — everything is decided here: permissions, plan, limits)

Continue with Connect your assistant for the actual configuration blocks. If you also want your own backend to talk directly to the public API, with the same key, see My own AI and my backend, talking to my data.