[Bug] Korean text renders as ◆ symbols in Chat panel when using Auto model mode

Support Bug Reports
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1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

[Bug] Korean text renders as ◆ symbols in Chat panel when using Auto model mode

Bug Description

When Agent model is set to Auto, all Korean characters in AI responses
appear as ◆ (broken glyphs) in the chat panel.

Setting the model explicitly to Claude Sonnet 4.6 resolves the issue completely.

Steps to Reproduce

  1. Set Agent model to Auto
  2. Ask any question in Korean
  3. Korean characters in response display as ◆ symbols

Workaround

Manually fix the model to Claude Sonnet 4.6 → Korean renders correctly.

Suspected Cause

Auto mode may route to a model that outputs Korean in NFD (decomposed Unicode).
Cursor’s chat renderer does not handle NFD Korean correctly.

Environment

  • OS: Windows 10
  • This likely affects ALL Korean users in Auto mode.

Steps to Reproduce

Bug Description

When Agent model is set to Auto, all Korean characters in AI responses
appear as ◆ (broken glyphs) in the chat panel.

Setting the model explicitly to Claude Sonnet 4.6 resolves the issue completely.

Steps to Reproduce

  1. Set Agent model to Auto
  2. Ask any question in Korean
  3. Korean characters in response display as ◆ symbols

Workaround

Manually fix the model to Claude Sonnet 4.6 → Korean renders correctly.

Suspected Cause

Auto mode may route to a model that outputs Korean in NFD (decomposed Unicode).
Cursor’s chat renderer does not handle NFD Korean correctly.

Environment

  • OS: Windows 10
  • This likely affects ALL Korean users in Auto mode.

Operating System

Windows 10/11

Version Information

Version: 3.0.16 (user setup)
VSCode Version: 1.105.1
Commit: 475871d112608994deb2e3065dfb7c6b0baa0c50
Date: 2026-04-09T05:33:51.767Z
Layout: editor
Build Type: Stable
Release Track: Default
Electron: 39.8.1
Chromium: 142.0.7444.265
Node.js: 22.22.1
V8: 14.2.231.22-electron.0
OS: Windows_NT x64 10.0.26200

Does this stop you from using Cursor

No - Cursor works, but with this issue

5

Hey, thanks for the detailed report. This is a known issue. Auto mode routes requests to the Composer 2 Fast model, which incorrectly handles CJK characters like Korean, Japanese, Chinese, and so on.

The team is aware, and we’ve gotten dozens of similar reports over the last few days. For now, the only workaround is the one you already found. Manually select a specific model like Claude Sonnet 4.6 or GPT instead of Auto.

Related threads for context:

Let me know if you run into anything else.

6

A post was merged into an existing topic: [BUG]Korean characters broken (encoding issue) in Composer/Agent