Create Tool records and pass them through AgentSdk.DefineTool(...). A tool can include:
- JSON
Parameters shown to the model
InputSchema, OutputSchema, and EventSchema validation delegates- a per-tool
Timeout and asynchronous Execute delegate
- unconditional or conditional approval
OnToolCalled and OnResponseReceived for interactive work- next-turn overrides and recoverable tool-error handling
Use RuntimeContext.EmitProgress for preliminary results, SetContext for application context, and CancellationToken for cancellation-aware dependencies.
Independent tools can run concurrently through ToolExecutionConfig. Saved tool-result messages retain model call order even if execution finishes in a different order.
Last modified on July 26, 2026
