Description

Environment

• OS: Windows 10
• Terminal: wezterm
• Shell: PowerShell 7.4.7
• Bun version: 1.3.10
• Node.js: Works correctly
  Problem
  When running opencode-cli on Windows with wezterm terminal, ANSI escape codes are displayed as literal text instead of being rendered as colors/styles.
  Example of corrupted output:
  m┃H Build [
  38; ssion - 2026-03-09T02:30:38.791Z █ 2
  0m 8
  ;238m续 3
  8;2 55m [
  12;4H
  ;
  30m█ 3
  0;30;30m█ 4
  8;2;3 m█
  The escape sequences like [38;2;255;255;255m, [30m, [48;2;30;30;30m
  should render colors, but are shown as plain text.
  Reproduction Steps

1. Install Bun on Windows

2. Use wezterm as terminal

3. Run any Bun-based CLI with colored output

bun -e "console.log('\x1b[31mRed\x1b[0m')"

Expected: "Red" in red color

Actual: "[31mRed[0m" as literal text

What I've Tried

1. ✅ Node.js works correctly:
   node -e "console.log('\x1b[31mRed\x1b[0m')"

   Output: Red (in red color)

2. ❌ Setting FORCE_COLOR:
   $env:FORCE_COLOR = "1"

   No effect

3. ❌ Setting TERM variables:
   $env:TERM = "xterm-256color"
   $env:COLORTERM = "truecolor"

   No effect

4. ❌ UTF-8 encoding:
   chcp 65001

   No effect

5. ❌ Modified wezterm.lua:
   config.set_environment_variables = {
   TERM = 'xterm-256color',
   COLORTERM = 'truecolor',
   }
   No improvement.

6. ✅ PowerShell native colors work:
   Write-Host "Red" -ForegroundColor Red

   Works correctly

7. ❌ Both opencode versions affected:

   • npx opencode - same issue
   • npx oh-my-opencode - same issue

Environment Variables Check
$env:TERM # xterm-256color ✓
$env:COLORTERM # truecolor ✓
$env:TERM_PROGRAM # WezTerm ✓
chcp # 65001 (UTF-8) ✓

All settings appear correct.
Root Cause Analysis

• Node.js correctly detects the terminal as TTY and renders ANSI codes
• Bun appears to not properly handle ANSI escape sequences on Windows + wezterm
• The issue is specific to Bun on Windows with wezterm (not reproducible with Node.js)

Expected Behavior
ANSI escape codes should render as colors/styles, matching Node.js behavior.
Actual Behavior
ANSI escape codes are printed as literal text, making the UI unreadable.
Suggested Fix
Bun should properly detect Windows terminals (wezterm, Windows Terminal, etc.) and pass ANSI escape codes through correctly, similar to how Node.js handles them.

Plugins

No response

OpenCode version

No response

Steps to reproduce

No response

Screenshot and/or share link

No response

Operating System

No response

Terminal

No response