Feature Request: Add `toolChoice` Parameter for Tool Selection Control

[codewarnab]

Summary

Add a toolChoice parameter to control how the model selects tools, similar to the Vercel AI SDK.

Proposed Type

type ToolChoice = 'auto' | 'none' | 'required' | { type: 'tool'; toolName: string };

Value	Behavior
auto	Model decides whether to call tools (default)
none	Model must not call any tools
required	Model must call at least one tool
{ type: 'tool', toolName }	Model must call the specified tool

Usage Example

// Force tool usage
await session.send({
  prompt: "What's the weather in Seattle?",
  toolChoice: "required"
});

// Prevent tool usage
await session.send({
  prompt: "Explain how weather forecasting works",
  toolChoice: "none"
});

// Force specific tool
await session.send({
  prompt: "Get Seattle weather",
  toolChoice: { type: "tool", toolName: "get_weather" }
});

Reference

• Vercel AI SDK: toolChoice docs
• OpenAI: tool_choice parameter

Contribution

I'm willing to implement the SDK changes (types, session.send, tests, docs) once backend support is confirmed.