Sonnet Model returned error

Bug Reports
1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

Describe the Bug
hello,I can’t use sonnet model.But I have no MCP Tools.

Request ID: a961502c-684d-4b50-97a6-b7f764032691
{“error”:“ERROR_CUSTOM_MESSAGE”,“details”:{“title”:“Model returned error”,“detail”:“The model returned an error. Try disabling MCP servers, or switch models.”,“additionalInfo”:{},“buttons”:,“planChoices”:},“isExpected”:true}
ConnectError: [invalid_argument] Error
at UZc.$endAiConnectTransportReportError (vscode-file://vscode-app/tmp/.mount_CursorybTzmU/usr/share/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:6331:408701)
at rLo._doInvokeHandler (vscode-file://vscode-app/tmp/.mount_CursorybTzmU/usr/share/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:6948:21873)
at rLo._invokeHandler (vscode-file://vscode-app/tmp/.mount_CursorybTzmU/usr/share/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:6948:21615)
at rLo._receiveRequest (vscode-file://vscode-app/tmp/.mount_CursorybTzmU/usr/share/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:6948:20377)
at rLo._receiveOneMessage (vscode-file://vscode-app/tmp/.mount_CursorybTzmU/usr/share/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:6948:19194)
at _Pt.value (vscode-file://vscode-app/tmp/.mount_CursorybTzmU/usr/share/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:6948:17286)
at _e._deliver (vscode-file://vscode-app/tmp/.mount_CursorybTzmU/usr/share/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:49:2962)
at _e.fire (vscode-file://vscode-app/tmp/.mount_CursorybTzmU/usr/share/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:49:3283)
at tpt.fire (vscode-file://vscode-app/tmp/.mount_CursorybTzmU/usr/share/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:6316:12156)
at MessagePort. (vscode-file://vscode-app/tmp/.mount_CursorybTzmU/usr/share/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:8976:18439)

Steps to Reproduce

I just choose Sonnet4.5.

Operating System

Linux

Current Cursor Version (Menu → About Cursor → Copy)

Version: 2.1.39
VSCode Version: 1.105.1
Commit: 60d42bed27e5775c43ec0428d8c653c49e58e260
Date: 2025-11-27T02:30:49.286Z
Electron: 37.7.0
Chromium: 138.0.7204.251
Node.js: 22.20.0
V8: 13.8.258.32-electron.0
OS: Linux x64 6.8.0-88-generic

For AI issues: which model did you use?

Sonnet4.5

For AI issues: add Request ID with privacy disabled

Request ID: a961502c-684d-4b50-97a6-b7f764032691
{“error”:“ERROR_CUSTOM_MESSAGE”,“details”:{“title”:“Model returned error”,“detail”:“The model returned an error. Try disabling MCP servers, or switch models.”,“additionalInfo”:{},“buttons”:,“planChoices”:},“isExpected”:true}
ConnectError: [invalid_argument] Error
at UZc.$endAiConnectTransportReportError (vscode-file://vscode-app/tmp/.mount_CursorybTzmU/usr/share/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:6331:408701)
at rLo._doInvokeHandler (vscode-file://vscode-app/tmp/.mount_CursorybTzmU/usr/share/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:6948:21873)
at rLo._invokeHandler (vscode-file://vscode-app/tmp/.mount_CursorybTzmU/usr/share/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:6948:21615)
at rLo._receiveRequest (vscode-file://vscode-app/tmp/.mount_CursorybTzmU/usr/share/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:6948:20377)
at rLo._receiveOneMessage (vscode-file://vscode-app/tmp/.mount_CursorybTzmU/usr/share/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:6948:19194)
at _Pt.value (vscode-file://vscode-app/tmp/.mount_CursorybTzmU/usr/share/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:6948:17286)
at _e._deliver (vscode-file://vscode-app/tmp/.mount_CursorybTzmU/usr/share/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:49:2962)
at _e.fire (vscode-file://vscode-app/tmp/.mount_CursorybTzmU/usr/share/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:49:3283)
at tpt.fire (vscode-file://vscode-app/tmp/.mount_CursorybTzmU/usr/share/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:6316:12156)
at MessagePort. (vscode-file://vscode-app/tmp/.mount_CursorybTzmU/usr/share/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:8976:18439)

Does this stop you from using Cursor

Sometimes - I can sometimes use Cursor

2

Hey, thanks for the report. Let’s try a few diagnostic steps to narrow down the cause:

  1. Run network diagnostics:

    • Go to Cursor Settings > Network > Run Diagnostics
    • Share any errors that appear

  2. Test without extensions:

    • Run cursor --disable-extensions in the terminal
    • Try using Sonnet 4.5 in the new window
    • If it works, one of your extensions is likely causing the issue

  3. Quick questions:

    • Are you using a VPN, corporate network, or antivirus/firewall?
    • Does creating a completely new Agent chat help, or does the error appear immediately?
    • Can you try Opus 4.5 or another model - do they work?

Let me know what these tests show.