CLAUDE_CONTEXT_COLLAPSE_MODEL

Updated October 14, 2026 by Alex Sorokoletov

CLAUDE_CONTEXT_COLLAPSE_MODEL is a Claude Code environment variable. Removed between v2.1.269 and v2.1.283, so current releases ignore it. It is not in the official reference.

How to set it

For one session, export it in the shell that starts Claude Code:

export CLAUDE_CONTEXT_COLLAPSE_MODEL=<value>
claude

To apply it to every session, add it to the env object of a settings file:

// ~/.claude/settings.json
{
  "env": {
    "CLAUDE_CONTEXT_COLLAPSE_MODEL": "<value>"
  }
}

Related variables

• CLAUDE_CONTEXT_COLLAPSE: Collapses context on the fly, with a dedicated model to do it.
• CLAUDE_CODE_AUTO_MODE_PRIOR_ASSISTANT_CONTEXT: Feeds prior assistant turns into the decision, so the classifier can see the reasoning behind an edit.
• CLAUDE_CODE_AUTO_MODE_SIBLING_CONTEXT: Includes sibling files (or sessions) when classifying.
• CLAUDE_CODE_DISABLE_1M_CONTEXT: Disable extended 1M token context window.
• CLAUDE_CODE_SAVE_HOOK_ADDITIONAL_CONTEXT: Extra context passed to save hooks.
• CLAUDE_CODE_RESUME_TOLERATES_CONTEXT_APPENDS
• CLAUDE_CODE_RESUME_TOLERATES_CONTEXT_SEEDS
• CLAUDE_AFTER_LAST_COMPACT: Request only conversation logs after last compaction.

Frequently asked questions

All variables, searchable: Claude Code environment variables.