Tools & MCP
Connect your assistant to data, APIs, external services, and devices.
Tools let your assistant do more than answer from its built-in knowledge. Depending on the job, you can use built-in tools, add your own HTTP API, connect an MCP server, or let a device provide tools during a voice session.
Which Option Should I Use?
| Need | Use |
|---|---|
| Search documents, remember users, search the web, or generate images | Built-in Tools |
| Call a simple HTTP API that you own | Custom API Tools |
| Connect an existing MCP server by URL | MCP Server |
| Use MCP servers on your computer or private network without a public URL | MCP Endpoint |
| Control capabilities exposed by an ESP32 device | Device Tools |
How Tool Calls Work
When a user asks for something that needs external data or an action, the assistant decides whether to call a tool. Most tool results are passed back to the AI model so it can produce a natural final answer.
Some tools respond directly. For example, image generation can return an image in chat, and a voice music tool can return an audio file for playback.
Choose Where A Tool Runs
Every tool can be limited to where it runs: the app, the website widget, the Developer API, voice, and messaging apps. Use it to keep a tool that changes data, such as one that creates orders, out of the public widget, or to keep voice-only tools out of chat.
- Open the Admin Panel and select the assistant.
- Find the tool: Tools for built-in and custom API tools; MCP for MCP servers (open a server's tools) and MCP Endpoint tools.
- Click the entries in the Available in column, tick where the tool may run, and click Save.
Some tools only work in certain places. For example, Music runs only in voice, so the others cannot be ticked. Turning a tool off stops it everywhere.
Building your own MCP server? A tool can declare where it works by listing app, widget, api, voice or messaging in _meta.assistant_platform.surfaces. The assistant offers it only there, and the admin panel greys out the rest.
Plan Access
MCP is available on all plans (including Free). Whether you can see and use MCP still depends on your role in the assistant. See Plans & Pricing for per-plan details.
If MCP is not visible in the admin UI, check your role permissions for the assistant.