Claude Opus 4.6 returns "Invalid Request" after being restored

[burhanalassad]

Craft Agents Version

0.11.4

Operating System

Windows 11

OS Version

Windows 11 24H2

AI Provider

Anthropic API (direct)

Model

Claude Opus 4.6

Description

After the recent update that restored Claude Opus 4.6 (following my support request), I can no longer use the model.

Every request immediately fails with the following error:

"Invalid Request
The API rejected this request.

If this keeps repeating, the conversation may have grown too large — try /compact or start a new session.

No detailed error info available — check the app's main process log for the raw response."

The issue happens even in a new conversation, so it does not appear to be caused by conversation length.

Steps to Reproduce

1. Open Craft Agents v0.11.4.
2. Select Anthropic API (direct).
3. Choose Claude Opus 4.6.
4. Start a new chat.
5. Send any simple prompt (e.g. "Hello").
6. The request immediately fails with "Invalid Request".

Expected Behavior

Claude Opus 4.6 should process the request normally and return a response.

Actual Behavior

Every request is rejected with:

"Invalid Request
The API rejected this request."

The UI suggests that the conversation may be too large, but the same error occurs in a completely new conversation.

Screenshots / Screen Recordings

Attached screenshots of the error message.

Debug Logs

I can provide the main process debug logs if needed.

Additional Context

Craft Agents Version: 0.11.4
Operating System: Windows 11 24H2
AI Provider: Anthropic API (direct)

This issue started after the update that restored Claude Opus 4.6.
Other models work as expected. The problem appears to affect only Claude Opus 4.6.