autoCompactWindow
A Claude Code settings key, read out of the shipped bundle. It has been in the build since v2.1.138, including the newest one read.
What it is
Set how full the context gets before Claude Code [compacts](/docs/en/context-window)
Anthropic's own wording. Read off Claude Code settings reference, captured 2026-08-28.
Presence across releases
| Releases | Reading | Declared type | Default |
|---|---|---|---|
| 2.1.245 – 2.1.250 5 releases | never mined | — | — |
| 2.1.138 – 2.1.243 95 releases | in the build | — | — |
A row reading never mined is a release with no archived bundle behind it. Nothing was read out of it, so nothing here says whether the name was in it. A declared type or a default is only ever what that release's own bundle stated.
Changelog entries naming it
-
v2.1.223Startup warning when CLAUDE_CODE_DISABLE_1M_CONTEXT can't actually be enforced
If your 1M-context disable flag has no effect on your model, startup now tells you and points at the real setting.
named in this entry
-
v2.1.221New --autocompact flag for the auto-compact window
You can set the auto-compact window at launch with --autocompact, using auto or 100k to 1M.
named in this entry
Documentation pages
- Claude Code settings reference reference table Claude Code CLI
- Claude Code settings reference table Claude Code CLI
- Environment variables mentions it Claude Code CLI
- Model configuration mentions it Claude Code CLI
A reference table page is one whose own table defines this name, and it is where the description above came from. A page that mentions it carries the name somewhere in its text and may say nothing about it at all. Every page carrying it.
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.