Introducing Structured Outputs in the API

OpenAI released Structured Outputs on Aug 6, 2024, making model outputs conform to developer-supplied JSON Schemas; `gpt-4o-2024-08-06` scored 100% on complex schema-following evals versus under 40% for `gpt-4-0613`. The feature is enabled with `strict: true` in function calling and works on tool-supporting models including `gpt-4-0613`, `gpt-3.5-turbo-0613`, and later. The key shift is constrained decoding plus schema training, not just valid JSON from JSON mode.

Why it matters: HKR-H/K/R all pass: OpenAI moves from 'valid JSON' to strict schema adherence and publishes a 100% vs <40% reliability gap. I keep it at 84 because this is a high-value API capability update, not a new frontier-model launch or company-level industry event.