Mid-session effort switching on Opus 5.5 preserves prompt cache in Claude Code v2.1.280+
lydiahallie · x · 2026-09-23
Lydia Hallie confirms that switching effort levels mid-session on Opus 5.5 no longer invalidates your prompt cache in Claude Code — as long as you're on version v2.1.280 or later.
Practical cost tip for anyone toggling between high reasoning and cheaper modes within a long session.
Related event: Switching Effort Mid-Session in Claude Code No Longer Breaks Prompt Cache(4 posts)→
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