What
On Windows, Claude Code renames environment variables to their standard spelling when they are written in a different case. Environment variables are named settings passed in from your system or shell. That list now includes CLAUDE_CONFIG_DIR, so a variable named claude_config_dir, for example, is treated as CLAUDE_CONFIG_DIR.
Why
Windows does not care about upper or lower case in these names. If you set this variable in a different case, Claude Code now picks it up instead of missing it.
Names in the bundleCLAUDE_CONFIG_DIR
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Added since
A small documentation edit on Hosting the Agent SDK touched a line naming CLAUDE_CONFIG_DIR after this was published.
* Point `CLAUDE_CONFIG_DIR` at a per-tenant directory so tenants do not share the `~/.claude.json` global config. When each config directory serves one working directory and you don't pass a [`SessionStore`](/docs/en/agent-sdk/session-stor…agent-sdk/hosting see the edit
Confirmed since
Anthropic's documentation has since written up CLAUDE_CONFIG_DIR, on Environment variables.
Between settings files, `env` values follow [settings precedence](/docs/en/settings#settings-precedence), so a managed settings entry overrides the same variable in user or project settings. Project and local settings can't set some variab…env-vars see the edit
One source agreesOne thing we can check says the same as this entry.
Anthropic's documentation agrees
Anthropic's documentation has since written up CLAUDE_CONFIG_DIR, on Environment variables.