Cmd. /fast
Switches the supported model's fast processing path. It is separate from reasoning effort and may have different billing or quota rules.
Key takeaways
- Toggle fast mode.
- Check the input surface and availability before using the examples below.
Purpose
Toggle fast mode.
/fast [on|off]Availability
| Field | Value |
|---|---|
| Input surface | Running CLI prompt |
| Kind | Built-in |
| Status | Current reference |
| Aliases | — |
| Documented minimum | Not specified |
| Reviewed against | 2026-09-22 · Claude Code 2.1.278 |
The installed command menu and account or organization settings determine availability.
Examples
/fastEffects and persistence
Switches the supported model's fast processing path. It is separate from reasoning effort and may have different billing or quota rules.
Remote sessions
Cloud and self-hosted-runner Remote sessions honor the host fast-mode setting or /fast where organization policy permits.
Cautions
Fast mode has its own availability and pricing. Do not treat it as a lower reasoning-effort setting.