🚨 Critical: Cascade Errors Repeatedly Occur When Using Claude Sonnet 4 in Latest Stable Windsurf

[Fahad9918]

Hello Windsurf team,

I am consistently encountering Cascade internal errors while using the latest stable release of Windsurf IDE with Claude Sonnet 4 enabled.

🔎 Steps to Reproduce

1. Open Windsurf (latest stable version).

2. Select Claude Sonnet 4 as the model in Cascade.

3. Perform basic coding tasks (e.g., file editing, running simple refactors).

4. Within a few minutes, Cascade throws repeated errors:

5. Error: (Cascade error)

⚠️ Actual Behavior

Cascade frequently crashes or displays the above error.

This interrupts ongoing work, making Claude Sonnet 4 effectively unusable.

Restarting Windsurf or clearing cache does not resolve the issue.

✅ Expected Behavior

Cascade should operate smoothly with Claude Sonnet 4, without frequent internal errors.

🖥️ Environment

OS: [Windows 11 Pro]

Windsurf IDE Version: [1.12.3]

Model: Claude Sonnet 4

Network: Stable (no proxy/firewall issues)

📎 Additional Notes

This issue is critical because it blocks productive use of Claude Sonnet 4 inside Windsurf, which is one of the key advertised features. Immediate attention would be highly appreciated. 🙏

[broeder-j]

Not to mention that it also consumes credits. For me happens with other models like Gemini Pro too, but less frequent.
Sometimes just a re-prompt, or 'continue' works. sometimes this just fails again.

A better error message at least would be appreciated. Makes it hard to work if, half your prompts just crash in a 'in between state' with half done modifications.

[ReS4]

I'm also facing a lot of errors when using Claude Sonnet 4 and its thinking variant. The error says

"Error while editing file > The model produced an invalid tool call."

Once I asked it to describe what the problem is and it said :

File Path Error Analysis
The file path errors I encountered were due to accidentally using directory paths instead of file paths in the MultiEdit tool:

Incorrect attempts:

D:*\front\ (directory path - missing filename)
D:*\front (directory path - missing filename)
Correct path:

D:***\front\modules\catalog\router.py
(full file path)
The MultiEdit tool expects a complete file path including the filename, not a directory path. When I accidentally truncated the path and only provided the directory portion, the tool failed because directories don't have editable content.

This happens when I copy-paste paths carelessly or when auto-completion truncates the path. The solution is to always ensure the full file path with filename and extension is provided.

It is so frustrating and consumes a lot of credit for a simple task.

[Saidalo1]

Not only when using Claude Sonnet 4, but also on other models too.

[DailyDisco]

Not only when using Claude Sonnet 4, but also on other models too.

Any fix yet?