Matt Holden: structured output is LLMs' real magic, now at 300ms and nearly free

holdenmatt · x · 2026-09-18

Replying to James Cowling, Matt Holden says function calling / tool use / structured output was always his favorite LLM feature: turning unstructured intent into strict, validated schemas is "the magic you can actually program with." He notes the rest can now be shed for 300ms latency at near-zero cost, adding that he "f'ing hates JSON Schema."

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