Claude Opus 5

Claude Opus 5 is Anthropic’s top-tier model, tuned specifically for agentic coding — multi-file features, large refactors, and end-to-end implementation work rather than single-shot completions. Give it a full task specification up front and it tends to run the whole way to a finished result instead of leaving stubs behind.

Why it stands out

• Built for the hard 20% — the gap over cheaper models is widest on genuinely difficult, multi-step engineering work, not quick edits.
• 1M-token context window as both the default and maximum, so it can hold an entire codebase’s relevant context in one pass.
• Strong code review and bug-finding, with high precision alongside high recall — most of what it flags is real.
• Full effort ladder (low through max), so cost and latency can be tuned per task without switching models.

Good for

Teams running autonomous coding agents on genuinely hard problems — large refactors, new feature builds, and long agent loops where finishing the job matters more than shaving a few cents per call.