Claude Desktop RTL Patch

Smart RTL (Right-to-Left) support for Claude Desktop on Windows. Adds automatic Hebrew/Arabic text direction detection without breaking English or code blocks.

What it does

• Auto-detects RTL text in Claude's responses and input box

• Keeps code blocks LTR — no broken formatting

• Creates backups of all modified files with full restore support

• Automated Updates — Optional background service to automatically re-apply the patch when Claude updates

Quick Install

Open PowerShell and run:

irm https://raw.githubusercontent.com/shraga100/claude-desktop-rtl-patch/main/install.ps1 | iex

A UAC prompt will appear — click Yes to grant admin privileges.

Alternative: Download patch.ps1 and right-click → Run with PowerShell

Requirements

• Windows 10/11 with Claude Desktop installed

  Download Claude Desktop from claude.ai

• Node.js installed (npx must be available in PATH)

• Administrator privileges (the script will request elevation automatically)

⚠️ Windows Only: This specific patch is for Windows.

🍎 Mac Users: Try toboly's mac patch or soguy's mac patch. (Note: I have not personally tested these Mac versions, use at your own risk).

Menu Options

When you run the script, you will see the following interactive menu:

Option	Description
1. Install	Backs up originals and injects RTL support
2. Restore	Reverts all changes from backup files
3. Create Shortcut	Creates a desktop shortcut for quick 1-click updates
4. Enable Auto Re-Patch	Installs a watcher to re-patch Claude automatically after updates
5. Disable Auto Re-Patch	Removes the background watcher
6. Exit	Close the patcher

🔄 Keeping the Patch Updated (Automation)

Claude Desktop updates frequently, and each update will overwrite this patch. To make maintaining the RTL support effortless, the patcher includes two helpful features:

1. Desktop Shortcut (Option 3): This creates a shortcut on your Desktop named "Update Claude RTL". Double-clicking this will silently fetch and apply the latest patch without making you navigate the menu.

2. Auto-Updater Service (Option 4): This sets up a lightweight Windows Scheduled Task. It runs quietly in the background and detects exactly when a new claude.exe version is launched. Once it detects an update, it will automatically download and apply the patch, showing you a quick Windows notification when it's done.

How it works (Technical)

Claude Desktop is an Electron application distributed as a digitally signed package. Adding RTL support requires modifying the JavaScript inside the app — but this breaks the integrity checks Anthropic uses to verify the application. The patch handles this in three phases:

Phase 1 — ASAR Injection

Claude's UI code lives inside app.asar, a read-only archive format used by Electron. The script:

1. Extracts the ASAR archive using npx asar

2. Injects a small JavaScript snippet into the renderer files — this snippet detects RTL characters in real time and applies the correct text direction

3. Repacks the ASAR and computes the new SHA-256 hash of its header

Phase 2 — Hash Replacement in claude.exe

claude.exe contains the original ASAR hash hardcoded as an ASCII string. The script performs a direct byte-level search-and-replace inside the binary to update it to the new hash, so the app accepts the modified ASAR.

Phase 3 — Certificate Swap in cowork-svc.exe

cowork-svc.exe is a background service that verifies the authenticity of claude.exe using Anthropic's embedded certificate. After re-signing claude.exe with a new self-signed certificate, the script:

1. Locates the original Anthropic X.509 certificate inside cowork-svc.exe using binary pattern matching (searching for 0x30 0x82 near the string "Anthropic, PBC")

2. Generates a self-signed certificate small enough to fit in the same byte slot

3. Replaces the original certificate in-place, padding with 0x00 to preserve file size and binary offsets

4. Re-signs both claude.exe and cowork-svc.exe with the new certificate

5. Adds the certificate to the Windows trusted root store (LocalMachine\Root)

All original files are backed up before any changes. If anything fails, an automatic rollback restores the originals.

⚠️ Disclaimer

Please read before installing.

This patch modifies the internal binaries of Claude Desktop in ways that are not authorized by Anthropic. Specifically:

• It replaces Anthropic's code-signing certificate inside cowork-svc.exe with a self-signed certificate

• It adds that self-signed certificate to your Windows trusted root certificate store

• It bypasses the application's integrity verification mechanism

By installing this patch you accept the following:

1. Use at your own risk. The authors take no responsibility for any damage to your system, data loss, or application instability.

2. Anthropic may terminate your account if they detect unauthorized modifications to their software, per their Terms of Service.

3. Keep the repository trusted. If this repository were ever compromised, running the install command could execute malicious code with Administrator privileges. Always verify the source before running any irm | iex command.

4. This patch is temporary. Claude Desktop updates will overwrite the patched files. You may need to re-run the installer after each update (or use the built-in Auto-Updater).

5. Not a permanent solution. This exists only until Anthropic adds native RTL support. Please upvote and request this feature through official Anthropic channels.

This project is open source (MIT). Contributions to improve RTL accuracy are welcome — PRs are open. 🙏

Troubleshooting

"Node.js (npx) is required" — Install Node.js from nodejs.org and reopen PowerShell.

Service won't start after patching — Run the script again and choose Restore (option 2), then Install (option 1).

Claude updated and the patch broke — Run the "Update Claude RTL" desktop shortcut, or use the Auto-Updater. If doing it manually, delete any .bak files in the Claude app directory and run the installer again.

Uninstall

Run the script and choose option 2 (Restore). This restores all original files from backup and removes the self-signed certificate from your Windows certificate store. If you installed the Auto-Updater, choose option 5 to disable it.

License

MIT