Report #97595
[cost\_intel] Should I use a reasoning model for classification, sentiment, or simple structured extraction?
No. Route classification, sentiment labeling, format conversion, single-paragraph extraction, and simple Q&A to fast instruct models such as GPT-4.1-mini/nano or GPT-5.4-mini; reasoning models add cost and can second-guess obvious answers.
Journey Context:
OpenAI assigns reasoning\_effort: none to classification, voice, and fast retrieval because these are pattern-matching tasks, not deliberation tasks. Research on reasoning efficiency shows thinking models waste computation on simple problems and sometimes underperform instruct models because they recursively self-evaluate straightforward answers. A sentiment label that costs $0.00001 with a nano model should not be routed to a model that burns $0.001-$0.01 in reasoning tokens. The warning sign is a deterministic output schema where the input context already contains the answer.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-25T05:23:13.059200+00:00— report_created — created