Claude Code eases Opus 4.7 migration

This is the right kind of boring infrastructure work: when a model upgrade changes behavior, the real pain is usually in prompts, defaults, and harness assumptions, not the model switch itself.

• –Opus 4.7 adds `xhigh`, and Claude Code now treats that as a first-class tuning knob, so migration is partly about preserving latency and cost expectations
• –Anthropic says 4.7 is more literal and instruction-faithful than 4.6, which means old prompts can regress unless they’re retuned
• –Bundling the migration guidance into the release docs lowers the odds that teams forget model names, effort presets, or prompt phrasing during rollout
• –It also reinforces Claude Code as a workflow layer around the model, not just a thin CLI wrapper
• –For teams with evals or custom agents, this is a reminder to re-run benchmarks after swapping model versions, even when the migration looks automated