Terminal: ANSI colors reset after first character on diff lines

Description

When running git diff --color=always (or any command that outputs colored diff lines) in Claude Code's terminal, the ANSI color codes are not applied to the full line. The +/- prefix character is colored correctly (green/red), but the rest of the line resets to white/default.

This works correctly in a standard terminal (iTerm2, Terminal.app, VS within the claude terminal).

Repro

Run any colored diff in Claude Code's terminal:

git diff --color=always

Or:

echo -e '\033[32m+this entire line should be green\033[0m'

Expected

The entire added line is green, the entire deleted line is red — matching standard terminal behavior.

Actual

Only the + or - character is colored. The rest of the line renders in the default text color.

Screenshots

Normal terminal (correct):

<img width="670" height="276" alt="Image" src="https://github.com/user-attachments/assets/fac1c61e-c85d-4eb1-b291-09b256024a45" />

Claude Code terminal (incorrect):

<img width="610" height="224" alt="Image" src="https://github.com/user-attachments/assets/ed470936-fff0-4f6c-bde5-130bd7ddfa7f" />

(Screenshots show a custom git wrapper tool which calls git diff --color=always under the hood. The normal terminal colors the full line; Claude Code only colors the first character.)

Environment

• Claude Code version: 2.1.91 (visible in screenshot)
• Platform: macOS (Darwin 24.6.0)
• Terminal: claude code terminal vs iTerm2