Voice agent tool calling
Let agents call your APIs mid-conversation to look things up and take action.
- Tool kinds: builtin, webhook, client, MCP
- Unified tools surface at /v1/agents/{id}/tools
- Agents act on your systems in real time
Definition
Tool calling lets a voice agent do more than talk. Mid-conversation, it calls your APIs to look something up or take an action, then continues the call with the result. A caller asks to check an order; the agent calls the order tool and reads back the status, live.
Tool kinds
Four kinds share one surface. Builtin tools cover common actions. Webhook tools call your own endpoints. Client tools run on the caller’s side. MCP tools connect to Model Context Protocol servers. You mix them on a single agent as the workflow needs.
How it works
Tools attach to an agent through a unified surface at /v1/agents/{id}/tools. You define a tool once, describe when it should be used, and the agent invokes it whenever the conversation warrants. The result flows back into the same real-time exchange.
Why it matters
Tool calling is what turns an agent from an FAQ reader into something that completes tasks. Looking up an account, booking a slot, processing a change: these need live access to your systems, and tool calling is the bridge.
Frequently asked questions
What is voice agent tool calling?
What kinds of tools are supported?
How do I add a tool to an agent?
Start building
Let agents call your APIs mid-conversation to look things up and take action.