[Bug]: Claude "Auto-compact after" has no effect when CLAUDE_CODE_AUTO_COMPACT_WINDOW is set #35725

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/server

Steps to reproduce

1. Set Settings → Providers → Claude → "Auto-compact after" to 400000.
2. Add "CLAUDE_CODE_AUTO_COMPACT_WINDOW": "1000000" to the env block of ~/.claude/settings.json.
3. Start a Claude thread on a 1M-context model and keep working past 400k tokens.

Expected behavior

Claude compacts at the window set in "Auto-compact after", where the context meter draws its compaction tick (about 367,000 tokens).

Actual behavior

Claude ignores the T3 setting and uses the variable instead. The thread grew to 818k / 1m without compacting, while the meter kept its tick at about 367k, so compaction looks overdue or broken. Nothing shows that the setting has no effect.

T3 sends the setting as --settings {"autoCompactWindow":400000,...}, but Claude Code prefers CLAUDE_CODE_AUTO_COMPACT_WINDOW over autoCompactWindow. With the variable set, /autocompact 400k is refused with "CLAUDE_CODE_AUTO_COMPACT_WINDOW is set and takes precedence. Unset it to change this setting."

Impact

Minor bug or occasional failure

Version or commit

T3 Code desktop 0.1.9 (.deb); still in the code on main @ 587deab

Environment

Ubuntu 26.04, Claude Code 2.1.322, Claude Opus 5.5 (1M window)

Notes

• First reported as a comment on #33798. fix(server): Claude context meter honours CLAUDE_CODE_AUTO_COMPACT_WINDOW #33806 fixed that issue's case (setting empty, variable set). When the T3 setting is filled, resolveAutoCompactWindow still returns it without checking the variable, and the launch never overrides the variable.
• Claude Code applies env from --settings above the settings files, so T3 can make its setting take effect by also sending it as CLAUDE_CODE_AUTO_COMPACT_WINDOW in that env, as it already does for ENABLE_TOOL_SEARCH. Checked with Claude Code 2.1.323: with the variable at 1000000 in a project .claude/settings.json, adding --settings '{"env":{"CLAUDE_CODE_AUTO_COMPACT_WINDOW":"400000"}}' makes /autocompact report 400k tokens (from CLAUDE_CODE_AUTO_COMPACT_WINDOW).

Workaround

Remove the variable from settings.json. New sessions then use the T3 setting.