[BUG] [iPadOS] Korean character composition broken - displays decomposed jamo instead of syllables

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?

[iPadOS] Korean character composition broken - displays decomposed jamo instead of syllables

Bug Report: Korean Character Composition Broken in Claude CLI Interactive Mode

Environment:

• Terminal App: Termius v7.3.2
• Device: iPad (iPadOS 26.2.1)
• Claude CLI Version: 1.0.24 (or run claude --version to check)
• Input Method: Korean (Hangul)
• Hardware Keyboard: Used

Issue:
When using Claude CLI in interactive mode, Korean text input is completely broken. Characters are decomposed into individual consonants (ㄱ,ㄴ,ㄷ...) and vowels (ㅏ,ㅓ,ㅗ...) instead of being properly composed into syllables.

Steps to Reproduce:

1. Open Termius v7.3.2 on iPad (iPadOS 26.2.1)
2. Launch Claude CLI with claude command
3. Switch input language to Korean using any method
4. Try to type Korean text (e.g., "한글입력" meaning "Korean input")

Expected Behavior:
Korean characters should compose properly into syllables:

What Should Happen?

Actual Behavior:
Korean characters appear decomposed into individual jamo (consonants/vowels):
ㅎ ㅏ ㄴ ㄱ ㅡ ㄹ ㅇ ㅣ ㅂ ㄹ ㅕ ㄱ

Important Notes:

• Korean input works PERFECTLY in the regular terminal (bash/zsh) before entering Claude CLI
• This issue ONLY occurs after entering Claude's interactive mode
• The problem persists even in /vim mode
• English input works normally in Claude CLI

Comparison:

| Location | Korean Input Status |
|----------|-------------------|
| Termius Terminal (bash/zsh) | ✅ Works perfectly |
| Claude CLI Interactive Mode | ❌ Completely broken |
| Termius + vim/nano editors | ✅ Works perfectly |
| Other iPadOS apps | ✅ Works perfectly |

Technical Details:
This appears to be an issue with how Claude CLI's interactive input mode handles IME (Input Method Editor) composition events on iPadOS. The CLI is likely reading individual keystrokes before the IME can compose them into complete characters.

Test Results:

• Tested on: iPad with iPadOS 26.2.1, Termius 7.3.2
• Tested with: Hardware keyboard (Globe key for language switch)
• Same issue occurs whether using software or hardware keyboard for Korean input

Workaround:
Currently have to:

1. Write Korean text in Notes app or other text editor
2. Copy the text
3. Paste into Claude CLI

This severely impacts usability for non-English users.

Impact:
Critical - Makes Claude CLI effectively unusable for Korean (and likely other CJK languages: Chinese, Japanese) users on iPadOS.

Related Issues:
This is a similar problem to what many CLI tools face with CJK input on mobile platforms, related to readline/input library handling of multibyte character composition.

Suggested Fix:
The Claude CLI input handler should properly support IME composition events and wait for the complete composed character before processing input, similar to how standard terminal emulators handle this on iPadOS.

Error Messages/Logs

Steps to Reproduce

[iPadOS] Korean character composition broken - displays decomposed jamo instead of syllables

Bug Report: Korean Character Composition Broken in Claude CLI Interactive Mode

Environment:

• Terminal App: Termius v7.3.2
• Device: iPad (iPadOS 26.2.1)
• Claude CLI Version: 1.0.24 (or run claude --version to check)
• Input Method: Korean (Hangul)
• Hardware Keyboard: Used

Issue:
When using Claude CLI in interactive mode, Korean text input is completely broken. Characters are decomposed into individual consonants (ㄱ,ㄴ,ㄷ...) and vowels (ㅏ,ㅓ,ㅗ...) instead of being properly composed into syllables.

Steps to Reproduce:

1. Setup iPad keyboard settings:

• Go to Settings → General → Keyboard
• Ensure both "English" and "Korean" are added to keyboard list
• Connect hardware keyboard (Magic Keyboard, Smart Keyboard, or any Bluetooth keyboard)

1. Open Termius on iPad:

• Launch Termius v7.3.2
• Open a local terminal or connect to any SSH server

1. Verify Korean input works in regular terminal:

• In the terminal (bash/zsh prompt), press Globe key (🌐) to switch to Korean
• Type: 한글 (Korean for "Hangul")
• Verify it appears correctly composed as: 한글
• This confirms Korean input is working in the terminal itself

1. Launch Claude CLI:

• Type: claude and press Enter
• Wait for Claude CLI to initialize and show the prompt

1. Attempt to type Korean in Claude CLI:

• Press Globe key (🌐) to switch to Korean input
• Try to type the same word: 한글

1. Observe the bug:

• Instead of seeing 한글, you will see decomposed characters: ㅎ ㅏ ㄴ ㄱ ㅡ ㄹ
• Each consonant and vowel appears separately instead of combining into syllables

Example comparison:

# In regular terminal (works correctly):
user@ipad:~$ 한글입력테스트
한글입력테스트

# In Claude CLI (broken):
claude> ㅎ ㅏ ㄴ ㄱ ㅡ ㄹ ㅇ ㅣ ㅂ ㄹ ㅕ ㄱ ㅌ ㅔ ㅅ ㅡ ㅌ ㅡ


### Claude Model

None

### Is this a regression?

Yes, this worked in a previous version

### Last Working Version

_No response_

### Claude Code Version

Claude^@Code^@v2.1.31

### Platform

Anthropic API

### Operating System

macOS

### Terminal/Shell

Other

### Additional Information

none