Claude Opus 4.8 shipped today. Here is what the launch post does not say about why your agents will feel different tomorrow.

Anthropic launched Opus 4.8 with a quiet set of changes that matter more than the benchmark deltas. Cache-aware routing inside agentic loops, a default 200k window that now actually behaves, and one regression that broke every prompt that hard-coded model='claude-opus-4-7'. Here is the migration you do before your standup.

Raccontata dadev.tothesequence.substack.com