Connectors overview

A connector is an MCP server whose tools get bridged into Excelente's tool registry at runtime. Once connected, the agent calls those tools exactly as it calls write_range, and the results land in the same conversation.

Connectors live under Capabilities → Connectors.

What MCP is#

The Model Context Protocol is an open standard for exposing tools and data to an AI agent. Excelente speaks browser JSON-RPC 2.0 over HTTP POST, the Streamable HTTP variant.

It cannot run stdio servers. A task pane is a sandboxed web view with no process to spawn, so a connector has to be reachable over HTTPS. Anything running locally needs an HTTP bridge in front of it.

Connected versus loaded#

Two independent states, and the distinction matters when you are managing cost.

The checkbox on each server row controls loading. Turning a server off keeps it connected but drops its tools from the toolbelt, which shortens the tool list the model reads on every turn.

On. This connector's tools are loaded into the agent. Click to turn off.

Connectors also toggle from the composer's brand marks and from the + menu.

Permissions for bridged tools#

Excelente reads the annotations each MCP tool declares about itself:

• Read-only and not destructive becomes a Read tool, which runs silently.
• Everything else becomes a Write tool, which routes through the approval card.

The rule is deliberately conservative. A server that does not describe itself carefully gets treated as capable of doing damage, and you see a prompt. See Approvals and undo.

Priming#

Some connectors are worth consulting before you ask anything. A preset can declare a priming recipe that Excelente runs for you:

• Instructions. The server's own instructions string joins the system prompt while the connector is on. It is treated as untrusted and capped in length.
• Catalog. A single call made once per connection whose result is cached and included each turn, so the agent knows what data is available without spending a call to find out.
• First turn. A call made automatically on the first message of a conversation, seeded into the transcript as an auto tool line.

auto lines are Excelente acting on your behalf, not the model requesting something. That badge is there so the transcript never implies the model did something it did not.

Priming recipes are token-cheap and fail soft. A connector that is down slows nothing down.

Connector states in the composer#

Each installed preset gets a brand mark right of the Undo button:

Clicking an error mark opens the connectors menu rather than toggling, because an expired session is not something a toggle fixes.

Servers you add yourself do not get a composer mark. Manage them from the Connectors panel or the + menu.

Persistence#

Connector configuration is stored in IndexedDB on your machine and reconnects when the pane opens. Credentials from an OAuth flow are held by that server's own session, not by Excelente.

What ships#

Two A.CRE connectors come preconfigured. See CRE Agents and the Intelligence Hub.

Any other MCP server can be added by name and URL. See Add your own MCP server.

Trust#

A connector's tools run inside your conversation with access to whatever the agent chooses to pass them, and its instructions text reaches the system prompt. Connect servers you trust, the same way you would think about installing a plugin. Excelente fences server-supplied instructions as reference material rather than commands, and a write-classified tool still stops at your approval card, which limits the blast radius without eliminating it.