Engineer's playbook: draft with Sonnet 5.5, build with Opus 5.5 to cut costs
every · x · 2026-09-29
Every shares Kieran Klaassen's three-phase workflow for using Claude Sonnet 5.5 and Opus 5.5 on the same project:
- Start with Sonnet for brainstorming and landing on an idea via fast feedback rounds.
- Switch to Opus for the heavy, detailed build once the direction is set.
- Return to Sonnet to iterate and polish.
The economics: Sonnet 5.5 costs $10/M output tokens vs Opus 5.5's $20, making prototyping cheaper — but price per token isn't the cost of a finished job. Klaassen found Opus more token-efficient on longer tasks, so he still switches for hard work.
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