/fast Command (Non-Interactive Variant) / Claude Code v2.1.116

What

New local command to toggle fast mode on or off, with support for non-interactive invocation.

Usage

/fast        # Toggle fast mode
/fast on     # Enable fast mode
/fast off    # Disable fast mode

Details

Evidence

Fast command definition (search for name: "fast") — CB7 at line ~530978

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

The build it came inv2.1.116

20 Apr 2026 · 34 entries, this one is #3.

Either side of it

Open the release →

Names in this entry

slash/fast
Toggle fast mode on or off. Run it while Claude is responding and Claude Code toggles fast mode without waiting for the turn to end, though the running turn finishes at its original speed. Before v2.1.242, Claude Code decided from a feature flag it fetched from Anthropic whether to run the command mid-turn or queue it until the turn finished, and always queued it in a session that doesn't fetch feature flags. Availability in non-interactive mode with -p is limited; see Toggle fast mode. Requires Claude Code v2.1.205 or later
settingoff
The feedback tool now says it covers Claude's own behaviour, not just product bugs.

Is this right?