fastMode

A Claude Code settings key, read out of the shipped bundle. It was in the build from v2.1.138 and was gone by v2.1.284.

Releases whose published page names fastMode.

1. v2.1.299 14 Oct 2026
   New hidden --fast-mode option turns fast mode on or off at launch

   A new hidden --fast-mode on or --fast-mode off command-line option sets fast mode for a launch, unless fastMode is already set elsewhere

   found in this entry's text

2. v2.1.299 14 Oct 2026
   Changing effort now also sends ultracode state to the session

   When effort changes, Claude Code now sends ultracode state along with the session's details, and changing fast mode now triggers its own handling

   found in this entry's text

3. v2.1.286 30 Sep 2026
   Fast mode is rechecked when a controlling program changes the model

   When a program turns on fast mode and changes the model in one settings update, Claude Code now runs a fast mode check afterwards

   found in this entry's text, named in this entry

4. v2.1.274 16 Sep 2026
   Fast/'penguin' mode org-status logic reworked for SDK contexts

   Fast mode's org-status checking logic was reworked to handle SDK-based sessions separately

   found in this entry's text

5. v2.1.274 16 Sep 2026
   Startup: fastMode/advisor settings sync extracted into shared helper

   Headless startup's fastMode and advisor settings sync moved into shared helper functions

   found in this entry's text

6. v2.1.274 16 Sep 2026
   Fast-mode policy override no longer requires the request flag

   Fast mode now switches to 'preference' whenever policy settings disable it, even if this request didn't ask for it

   found in this entry's text

7. v2.1.242 24 Aug 2026
   Cloud sessions accept only seven live settings changes

   Only seven settings can be changed mid-run against a cloud session; others are rejected by name.

   found in this entry's text

8. v2.1.221 3 Aug 2026
   Fast mode credit rejections show a notification instead of silently turning fast mode off

   Fast mode stays on and shows an error notification when credit limits reject overage.

   named in this entry, found in this entry's text

9. v2.1.39 10 Feb 2026
   Fast Mode Keyboard Toggle

   found in this entry's text

10. v2.1.36 7 Feb 2026
    New User Setting: fastMode

    found in this entry's text

The earliest release whose published evidence quoted fastMode was v2.1.259, 2 Sep 2026. That is the oldest release this project wrote about it, so it is a floor on the name's age and not the release that introduced it. It is not a presence reading: which builds carried the name is the table below.

One row per release since the first build this name was read out of. Absent means the build was read and the name was not in it, never mined means no bundle for that release was ever archived, and a declared type or a default is only ever what that release's own bundle stated.

Read out of the published npm bundle release by release, and out of Anthropic's own documentation as this site captured it. Nothing on this page is a description anybody here wrote about what the settings key does. All settings keys.