Opus 5 and Kimi 3 models in Agent Builder

Four new models are now available in the Agent Builder:

• Claude Opus 5 — Anthropic's most capable model for complex agentic and coding work.
• Opus 5 Thinking — the same model tuned for higher reasoning effort on tougher tasks.
• Kimi 3 — an open-weight frontier model with a 1M-token context window and image input.
• Kimi 3 (US) — US-hosted inference with zero data retention, at a 10% premium.

Open the Agent Builder, click the model dropdown, and pick one. Your existing agents don't change — the default model stays put, so nothing switches over unless you choose a new model yourself.