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Documentation›Connectors

Add your own MCP server

Point Excelente at any Streamable HTTP MCP server and its tools join the agent's toolbelt.

Any MCP server reachable over HTTPS can be added by name and URL.

Adding one#

Capabilities → Connectors, below the preset rows:

Or connect any external connector (MCP). Each added connector appears in the agent's toolbelt.

Two fields:

Field Rules
Name Lower-kebab: letters, digits, and hyphens. Forced lowercase as you type. Must be unique
URL A valid http:// or https:// address

Click Add Connector. Excelente handshakes immediately, and adding a server also turns it on.

Validation messages are specific:

Name must be lower-kebab: letters, digits, and hyphens only (e.g. 'acre-hub').

An MCP server named "acre-hub" already exists.

URL must be a valid http:// or https:// address.

The name is how bridged tools are tagged internally, which is how Excelente bulk-removes them when you disconnect. Pick something short and stable.

Requirements for the server#

  • Streamable HTTP. JSON-RPC 2.0 over HTTP POST. Excelente cannot spawn a stdio server, because a task pane has no process to spawn.
  • Reachable over HTTPS from the browser. The pane runs in a sandboxed web view. localhost is not reachable from Excel on the web, and a self-signed certificate will fail.
  • CORS configured to allow the origin your Excelente instance is served from (https://excelente.aiedge.ac for the hosted build).
  • Authentication in the URL or handled by the server. The add form takes a name and a URL. Servers that need a token generally issue a personal URL containing one. Excelente does not have a header field.

A local server can be exposed with a tunnel, but that URL is a credential and reaches whatever the tunnel points at. Be deliberate about it.

What you see once connected#

Each row in the server list shows its name, URL, a load checkbox, and a status:

Connecting…

Connected · 12 tools

Error · Failed to fetch

Errors are truncated at 60 characters. The most common causes are CORS, an expired credential in the URL, or a server that is not speaking Streamable HTTP.

Tool permissions#

Excelente reads the annotations each tool declares. Read-only and non-destructive tools run silently; everything else stops at the approval card. A server that does not annotate its tools gets the cautious treatment, which means prompts.

Turning tools off without disconnecting#

The checkbox on each row controls whether that server's tools are loaded into the agent:

Connecting a server also turns it on for chat. Turn one off to keep it connected without loading its tools.

Worth using. Every loaded tool is schema the model reads on every turn, so a server with forty tools that you need twice a week is better left off between uses.

Removing one#

The ✕ on a row, with an in-pane confirm:

Remove "acre-hub"? Its tools will be unregistered. — Remove

The confirm renders inside the panel because Excel for Mac's task pane does not implement native browser dialogs.

Storage#

Server configurations live in IndexedDB on your machine and reconnect when the pane opens. They are not synced between devices and are not sent anywhere.

If you are running a fork#

Preset connectors are declared in src/core/mcp/presets.ts, including their connect method, help copy, and any priming recipe. Adding a preset there gives it a composer brand mark and an entry in the setup flow. Any OAuth domain also has to be added to <AppDomains> in manifest.template.xml or the sign-in dialog will be blocked. See Architecture.