Unicode combining characters render as tiny glyphs in terminal output

Description

In Claude Code's terminal output, Unicode characters encoded in NFD form (decomposed) — a base character followed by a combining accent — render incorrectly. The combining accent appears as a separate, tiny glyph rather than being composed with the base character.

Example

The word Sautéed — when the é is encoded as e (U+0065) + combining acute accent (U+0301) rather than the precomposed é (U+00E9) — displays with a visibly tiny accent character floating next to the e.

* Sautéed for 30s   ← combining form: accent renders tiny
* Sautéed for 30s   ← precomposed form: renders correctly

Behavior

• Occurs consistently in Claude Code terminal output
• Does not occur in a regular shell session in iTerm2 with the same font
• Affects any output containing NFD-encoded Unicode combining characters (accented letters are the most common case)

Expected behavior

Claude Code should normalize Unicode output to NFC (precomposed) form before rendering, or the terminal renderer should handle combining characters correctly — consistent with how standard terminals handle them.

Environment

• Platform: macOS 25.3.0
• Terminal: iTerm2
• Shell: zsh
• Claude Code terminal theme: dark-ansi