tool calling and function invocation with multi-step agent loops
Implements tool calling via a schema-based function registry that maps tool definitions (name, description, parameters as Zod schemas) to handler functions. Supports native tool-calling APIs (OpenAI functions, Anthropic tools, Google function calling) with automatic request/response normalization. Provides toolUseLoop() for multi-step agent orchestration: model calls tool → handler executes → result fed back to model → repeat until done. Handles tool result formatting, error propagation, and conversation context management across steps.
Unique: Provides a unified tool-calling abstraction across 15+ providers with automatic schema normalization (Zod → OpenAI format → Anthropic format, etc.). Includes toolUseLoop() for multi-step agent orchestration that handles conversation context, tool result formatting, and termination conditions, eliminating manual loop management. Tool definitions are TypeScript-first (Zod schemas) with automatic parameter validation before handler execution.
vs alternatives: More provider-agnostic than LangChain's tool calling because it normalizes across OpenAI, Anthropic, Google, and others with a single API; simpler than LlamaIndex tool calling because it uses Zod for schema definition, enabling type inference and validation in one step; includes built-in agent loop orchestration whereas most alternatives require manual loop management.