[BUG] Glyph U+23BF renders as tofu in the Claude Code TUI

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

U+23BF ⎿ (DENTISTRY SYMBOL LIGHT VERTICAL AND BOTTOM RIGHT) renders as tofu in the Claude Code TUI

What Should Happen?

Symbol should be more common. Claude Code's TUI uses ⎿ (and its mirror ⎾, U+23BE) as corner bracket characters to draw the edges of input boxes and bordered UI elements. They're from the "Dentistry Symbols" block but happen to be perfect L-shaped corners for box-drawing purposes. You'll also see U+23B8/U+23B9 (⎸⎹) used as vertical bars in the same UI. It's a quirky choice since the Box Drawing block (U+2500–U+257F) has more conventional alternatives.

Error Messages/Logs

No fonts on my system, including the popular nerdfont variant of JetBrains Mono has this glyph.

Steps to Reproduce

Open the Claude Code TUI. See: ⎿  (0x23bf)

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.84 (Claude Code)

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

_No response_