Bring your automation

What works today, stated plainly

Connecting a server, discovering its tools, allow-listing them, and assigning them to an agent are live. Declarations are recorded and audited now; agents execute those declarations at call time as the agent runtime rolls out — until then a declaration is recorded, not executed. We would rather tell you that than let you assume a flow is running when it is not.

Before you start

• A Nexus workspace account — sign in and open the Connections tab.
• An MCP endpoint URL (and, for most platforms, a bearer token) from your automation tool. Where to find it:
• Zapier: in your Zapier account, open MCP and create a server. Zapier gives you your personal endpoint — it looks like https://mcp.zapier.com/api/mcp/mcp — and a secret bearer token. Add the Zapier actions you want exposed as tools in Zapier's own MCP editor.
• Make: use the MCP tools in your scenario, then copy the remote MCP URL and token Make generates.
• n8n: add the MCP Server Trigger node to a workflow and use the endpoint URL and bearer token it produces.
• Any other remote MCP server works the same way — the form takes any https:// URL.

Connect it — step by step

1. In your workspace, open Connections.
2. Switch the tab to Advanced (Connectors mode is the plain-language view of the same machinery).
3. Click Add a custom server.
4. Give it a Name you will recognise ("Zapier — invoicing flows").
5. Paste the Endpoint URL (must be https://).
6. Set Auth to Bearer token and paste the token your platform gave you.
7. Click Discover tools — Nexus asks the server for its tool list and shows it beside the form. For a not-yet-registered server the token is used once, ephemerally, and never stored.
8. Set each tool's allow-list level: off (not callable), r (read), or rw (read and write). Everything starts off — nothing is callable until you allow it.
9. Click Register server. The connection now appears as a row you can expand to see the token fingerprint and re-visit the allow-list at any time.

Where your token lives

The token you paste is stored encrypted in your workspace vault, never in plain text, and never shown again — the connection row shows only a short fingerprint so you can tell which token is which. Discovery over an unregistered server uses the token once and forgets it.

Costs you should know about

Nexus does not charge for connections, but the platform you connect might. Zapier, for example, meters MCP tool usage as Zapier tasks on your Zapier plan. Check your automation platform's own metering before you let agents fire flows in a loop.

If discovery comes back empty

An empty tool list almost always means one of: the URL is not the MCP endpoint (check for the exact path your platform documents), the token expired or was rotated, or the platform has no actions published to its MCP surface yet. Fix the URL or token and click Re-discover. A re-discovery keeps your choice for tools the server still offers and resets the rest to off.