Sandbox sets TMPDIR but doesn't create the directory

Bug

The sandbox sets TMPDIR=/tmp/claude in the subprocess environment, but does not create the /tmp/claude directory. On macOS, /tmp is cleared periodically by the system, so this directory vanishes between sessions.

This causes any tool that creates temp files to fail:

$ uv run ruff check .
error: No such file or directory (os error 2) at path "/tmp/claude/.tmphGWqIr"

Also affects pytest, uv run generally, and anything else that respects TMPDIR.

Expected behavior

If the sandbox sets TMPDIR, it should ensure the directory exists (e.g., mkdir -p $TMPDIR before launching the subprocess).

Workaround

mkdir -p /tmp/claude at the start of a session, or prefix commands with TMPDIR=/private/tmp/claude-502.

Environment

• macOS 15 (Darwin 25.2.0)
• Claude Code CLI

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Created with assistance from Claude Code