/model switches the AI model Claude Code uses. Before switching, it now runs an extra check. That check can:
- refuse the switch and show a message
- ask you to confirm, sometimes also asking for a reason
The check takes into account where the current turn came from and which MCP servers are involved. MCP servers are add-ons that give Claude extra tools. When the check objects, the switch is not saved as your default for new sessions either. Any pending notes are now added to the end of what /model prints.
Previously the only things that could stop a switch were managed settings and the confirmation about losing cached context. A switch can now also be refused or need extra confirmation under conditions Claude Code sets.
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
| `/fast` | Once an Owner [allows fast mode](/docs/claude-tag/admins/customize#allow-fast-mode), you [turn it on for one thread](/docs/claude-tag/users/models#run-a-thread-in-fast-mode) with `@Claude !fast` |claude-tag/concepts/for-claude-code-users see the edit
* Fixed Bedrock and Vertex startup model checks ignoring an enforced `availableModels` list, which could collapse `/model` to one Opus rowchangelog see the edit
What makes the check refuse or ask for confirmation is not known.
Anthropic's documentation has since written up /model, on Claude Code changelog.