Connect External Applications Through MCPs, CLIs, and APIs

Hermes cannot control Gmail, Google Calendar, Google Drive, Slides, Docs, social platforms, brokerages, or other services until it receives a supported connection. MCPs, command-line interfaces, and APIs are different ways of exposing an application's functions to the agent.

The connector is the bridge between reasoning and action. Hermes decides what should happen; the connector gives it an authenticated method for carrying out the action.

An MCP packages application tools in a form an agent can call. An API exposes functions programmatically. A CLI exposes functions through commands that Hermes can run on the machine. The user does not need to treat these as identical technologies, but operationally they solve the same problem: they let Hermes communicate with an external application.

Composio acts as a gateway to many applications. The user connects accounts such as Google Calendar, Gmail, Slack, HubSpot, Linear, or social platforms in one place. Hermes then authenticates to the Composio MCP and gains access to the applications the user has authorized.

The Google Workspace CLI provides another route for Google services. It can expose Drive, Chat, Slides, Docs, and related functions. Hermes can install the CLI from its repository and guide the user through authentication.

After installation, the connection should appear in Hermes settings. A simple read test confirms that the connector works. The calendar example asks Hermes what is scheduled for the following day. Once the read succeeds, the same connection can be used for actions such as moving appointments or creating calendar entries.

An agent without connectors can advise but cannot operate the surrounding business. The moment it can inspect the calendar, read email, access project documents, publish content, or create a support ticket, it becomes part of an actual workflow.

Connectors also reduce manual transfer. Instead of copying information from several applications into chat, Hermes can retrieve the current information itself, combine it, and act on the result.

The connector design affects manageability. A gateway such as Composio centralizes authentication for many applications. A dedicated CLI may expose deeper functionality for a specific suite such as Google Workspace.

Use a consistent connection procedure:

1. Identify the exact action Hermes must perform, such as reading a calendar, drafting email,

editing a document, or publishing a post.

1. Select the available MCP, CLI, or API that exposes that action.
2. Connect the account in the provider's interface.
3. Ask Hermes to install or configure the connector and complete the authorization flow.
4. Confirm the connector appears in Hermes settings.
5. Run a read test using known information.
6. Only after the read test succeeds, test a small controlled write.

For Composio, connect the required applications first, then ask Hermes to set up the Composio MCP through the authorization link. Verify with a calendar query.

For the Google Workspace CLI, give Hermes the installation location, ask it to install the CLI, follow the authentication steps, and test access to the relevant Google service.

Keep connectors aligned with profiles. The personal profile should use personal accounts. A client profile should use only the client's approved accounts. A specialist agent should not inherit unrelated credentials.

Authentication is often the most difficult part of a connector setup. Providers can require different permissions and may expose different levels of functionality. A broad gateway is convenient, while a dedicated CLI may offer more direct control.

Each connector expands what Hermes can see and change. The connection should therefore be limited to the applications needed for the workflow, tested before automation, and reviewed when the profile's role changes.

External work requires an authenticated bridge. Choose the appropriate MCP, CLI, or API, verify it with a simple read, and add write capability only after the connection behaves correctly.