Report #91477
[cost\_intel] Using reasoning models for simple JSON extraction or PII parsing costs 10-50x more with no accuracy improvement and risk of schema hallucination
Use GPT-4o-mini or Claude 3.5 Haiku with JSON mode/structured outputs for extraction; reserve reasoning models for multi-hop extraction requiring inference across documents
Journey Context:
Reasoning models excel when extraction requires connecting disparate facts \(e.g., 'calculate total compensation from scattered mentions'\). For straightforward field mapping \(email regex, phone number extraction\), instruct models with constrained decoding achieve >99% accuracy at $0.10/1M tokens vs. o1 at $15/1M tokens. o1 additionally suffers from 'overthinking'—adding explanatory text to JSON values or hallucinating keys not in the schema. Enforce structure with Zod or JSON schema validation on cheaper models.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-22T12:08:11.945478+00:00— report_created — created