Gives an agent or model access to logic written in your own application. It is listed among the tools as type function with a name, a description and a JSON Schema describing its arguments; when called, your code does the work and passes the result back.
Also called function calling.
Read more: Microsoft Learn
In the Ultra Transcenders books
Each book explains Function tool in context, with comparison tables and the common traps.
Terms in this definition
- Agent
A specialised form of Microsoft Copilot set up for one particular job, pairing instructions with knowledge and skills. You can create one in Copilot Studio, SharePoint or Agent Builder, and administrators control them from the Microsoft 365 admin center.
- FUNCTION
Registered models count as functions in Unity Catalog, so this securable type governs them too: access is given through
GRANT ... ON FUNCTION, and REST calls passFUNCTIONassecurable_type. - JSON
Text-based format for structured data. ARM templates and Cosmos DB documents are written in it, and most Azure REST APIs exchange request and response bodies as application/json.
- Schema
The middle part of a Unity Catalog name (
catalog.schema.table), grouping tables, views, volumes, functions and models inside a catalog. A grant on it covers everything in it now and later, and nothing inside can be reached withoutUSE SCHEMA.
Related terms
- Structured outputs
Set
response_formatwith a JSON schema and a chat model's final answer will conform to it, whichever provider is involved, as Databricks smooths over the differences. Function calling has a schema too, though there it lists what the model may request to run. - Voice Live API
Real-time voice agents can be built on this fully managed, low-latency speech-to-speech service. One WebSocket brings together speech recognition, a generative model and text to speech, with optional avatars and function calling, and replies come back as audio rather than text alone.