[FEATURE]: Add RTL (Right-to-Left) language support in the chat panel

[datacodexlab]

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Describe the enhancement you want to request

Summary

OpenCode currently does not support RTL text rendering in the chat panel. Arabic, Hebrew, and Persian-speaking users experience broken text alignment and poor readability when writing in their native languages.

Problem

When a user types in Arabic (or any RTL language) in the chat input:

• Text alignment is LTR by default, making RTL text appear reversed or unreadable.
• There is no option to manually switch the chat panel direction.
• Mixed LTR/RTL content (e.g., Arabic prompt + English code) is not handled gracefully.

Proposed Solution

1. Auto-detect text direction using the Unicode Bidirectional Algorithm (bidi) — automatically switch alignment based on the first characters typed.
2. Manual toggle — allow users to set a preferred text direction in settings:

   {
     "chat": {
       "textDirection": "auto"
     }
   }

   Options: "auto" | "ltr" | "rtl"
3. Per-message direction — each chat bubble should render in the correct direction based on its content language.

Why This Matters

Arabic-speaking developers are a significant and growing user base in the Middle East and globally. RTL support is a basic accessibility requirement for these users and is standard in all major chat-based tools (Slack, Discord, VS Code chat extensions).

Without RTL support, Arabic developers are forced to write their prompts in English even when they prefer Arabic — this creates a significant barrier to adoption.

References

• Unicode Bidirectional Algorithm: https://unicode.org/reports/tr9/

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• [FEATURE]: Add RTL support in UI to Hebrew & Arabic #14257: Add RTL support in UI to Hebrew & Arabic (same feature request)
• RTL language support (Persian/Arabic) - characters appear reversed and disconnected #16875: RTL language support (Persian/Arabic) - characters appear reversed and disconnected (same problem)
• [FEATURE]:Add Hebrew (he) localization with RTL layout support #21676: Add Hebrew localization with RTL layout support (overlapping RTL/language support request)

Please review these issues and consider adding your input there instead of opening a new one.