TIL (Today I Learned) Notes

TIL: You can set IS_DEMO=1 to simplify the welcome screen of Claude Code. There are two types of welcome screens (shown below), and there’s no obvious logic behind which one appears for a given project — I found this annoying. After digging into it, I discovered an undocumented environment variable IS_DEMO¹ that forces the simpler one. Run IS_DEMO=1 claude, or set it in Claude Code’s settings.json under the env key.

TIL: $TMPDIR is an environment variable set by macOS (not fish-specific) that points to a per-user temporary directory. Its value looks something like:

/var/folders/xx/xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/T/

The path is unique per user and per boot session — macOS generates it under /var/folders/. Files here are:

• Automatically cleaned up by the system. macOS periodically purges files in /var/folders/ that haven’t been accessed recently (typically after 3 days of inactivity, managed by the periodic daily scripts). A reboot also clears them.
• Not shared across users, since each user gets their own subdirectory.

On Linux, $TMPDIR is often unset; the conventional fallback is /tmp.

TIL: When editing Markdown files in VS Code, you can paste URLs as formatted links via the markdown.editor.pasteUrlAsFormattedLink.enabled setting.

This setting was first introduced in June 2023, with the release of VS Code 1.80.

This is a nice quality-of-life feature. I used to type brackets, parentheses, and URLs manually, always wishing for a simpler way. I’m now using the smart option, which “smartly creates Markdown links by default when not pasting into a code block or other special element.”

Here’s a quick demo:

Paste URLs demo