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Tool calling lets a PAL trigger code while a conversation is happening - look something up, write to a CRM, hit a third-party API, or notify your frontend. Tools are reusable objects: create them once, and attach them to any number of PALs.
Skills vs tools: Tools are functions you define and attach for the LLM or Raven to call. Skills are Tavus-authored capabilities (search, presentation, Magic Canvas, etc.) you attach from the skill registry. A PAL can use both.

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Two in-call tool types

TypeTriggered byPages
LLM toolWhat the user says - the conversational LLM decides to call the tool.Tool Calling for LLM
Perception toolWhat Raven sees or hears in the audio/video streams.Tool Calling for Perception
Pick by setting origin on the tool: "llm", "vision", or "audio". A single PAL can hold both types.

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Post-call actions

Post-call actions are a third pattern: they run once after the conversation ends, with Tavus filling open arguments from the transcript and perception analysis and delivering the call for you. Set trigger_type: "post_call" (and omit origin) instead of using in-call origin values.

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Two delivery channels

Every tool dispatches via exactly one channel:
  • App message (default) - the call lands as a conversation.tool_call event your frontend handles.
  • API call - Tavus makes an HTTPS request to a URL you configure - your own callback endpoint or a third-party API directly.
See Tool Delivery for the request shape, URL templating, and response handling. See Tool Authentication for the auth types and how they map to outgoing headers.

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Quick start

  1. Create the tool at /v2/tools with a name, description, parameters JSON Schema, origin, and delivery.
  2. Attach it to a PAL at /v2/pals/{pal_id}/tools.
  3. Start a conversation with that PAL; the tool is now callable.
Legacy inline tools: Older integrations define tools directly on the PAL (layers.llm.tools, layers.perception.visual_tools, layers.perception.audio_tools). That path still runs for existing PALs but is deprecated for new work. See Legacy inline tool calling for how it behaves and how to migrate.