Function Calling With Schema Validation

via “schema-based function calling with structured output mode”

Cost-efficient small model replacing GPT-3.5 Turbo.

Unique: Uses constrained decoding at the token level to guarantee schema compliance rather than post-hoc validation, preventing invalid JSON generation before it occurs — similar to Outlines or Guidance but integrated directly into OpenAI's inference pipeline

vs others: More reliable than Claude's tool_use because it guarantees schema compliance at generation time rather than relying on model behavior; faster than Anthropic's approach because validation is built into decoding rather than requiring separate validation passes