- [new] Added
claude-sonnet-5as a supported model. - [changed] Updated default model selection to
claude-sonnet-5in agent and onboarding flows. - [new] Added support for the
computer-use-2025-11-24API beta header. - [changed] Adjusted model-facing instructions for code review harnesses, design defaults, effort levels, and token budgeting to account for
claude-sonnet-5behavior and its tokenizer.
Models & prompts
The release introduces claude-sonnet-5 and updates numerous system prompts to reference it as the new default. Guidance now covers stricter effort level handling, visual style consistency on design tasks, and recommendations for leaving sufficient max_tokens headroom. Plan mode and focus mode messaging were also refreshed for clarity.
Under the hood
Two new environment variables were added under the CLAUDE_5 group (CLAUDE_5_SONNET and CLAUDE_BG_SESSION_PERMISSION_RULESL). A new backend route for deployment runs was introduced.
Upgrade notes
Existing max_tokens settings tuned for earlier Sonnet models may need to be increased when using claude-sonnet-5 on long-running tasks due to the new tokenizer.