Fable-5 via AWS Bedrock not working

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

Request ID: 02340bfe-0e07-438d-bf3c-0a872f8bc64b
{“error”:“ERROR_OPENAI”,“details”:{“title”:“Unable to reach the model provider”,“detail”:“We encountered an issue when using your API key: Provider was unable to process your request\n\nAPI Error:\n\n\n10 validation errors detected: Value null at 'toolConfig.tools.1.member.toolSpec.name' failed to satisfy constraint: Member must not be null; Value null at 'toolConfig.tools.2.member.toolSpec.name' failed to satisfy constraint: Member must not be null; Value null at 'toolConfig.tools.3.member.toolSpec.name' failed to satisfy constraint: Member must not be null; Value null at 'toolConfig.tools.4.member.toolSpec.name' failed to satisfy constraint: Member must not be null; Value null at 'toolConfig.tools.5.member.toolSpec.name' failed to satisfy constraint: Member must not be null; Value null at 'toolConfig.tools.6.member.toolSpec.name' failed to satisfy constraint: Member must not be null; Value null at 'toolConfig.tools.7.member.toolSpec.name' failed to satisfy constraint: Member must not be null; Value null at 'toolConfig.tools.8.member.toolSpec.name' failed to satisfy constraint: Member must not be null; Value null at 'toolConfig.tools.9.member.toolSpec.name' failed to satisfy constraint: Member must not be null; Value null at 'toolConfig.tools.10.member.toolSpec.name' failed to satisfy constraint: Member must not be null\n”,“additionalInfo”:{},“buttons”:,“planChoices”:},“isExpected”:true}
[invalid_argument] Error
Rpe: [invalid_argument] Error
at iw1 (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:35723:27646)
at fog (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:35723:26375)
at hw1 (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:35724:7469)
at kog.run (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:35724:12370)
at async qle.runAgentLoop (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:48124:2927)
at async k7g.streamFromAgentBackend (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:48195:12809)
at async k7g.getAgentStreamResponse (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:48195:21069)
at async sut.submitChatMaybeAbortCurrent (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:35854:1995)
at async no (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:47078:33305)

Steps to Reproduce

Try to use “eu.anthropic.claude-fable-5” via AWS Bedrock in Cursor IDE and you hit this error

Expected Behavior

fable-5 works via AWS Bedrock

Operating System

MacOS
Linux

Version Information

Version: 3.7.21
VS Code Extension API: 1.105.1
Commit: 517f696d8ab6c53eb04fbfdaae705cd146bf3460
Date: 2026-06-07T21:46:09.237Z
Layout: editor
Build Type: Stable
Release Track: Default
Electron: 39.8.1
Chromium: 142.0.7444.265
Node.js: 22.22.1
V8: 14.2.231.22-electron.0
xterm.js: 6.1.0-beta.256
OS: Darwin arm64 25.5.0

For AI issues: which model did you use?

Fable-5

For AI issues: add Request ID with privacy disabled

02340bfe-0e07-438d-bf3c-0a872f8bc64b

Does this stop you from using Cursor

No - Cursor works, but with this issue

Thanks for the detailed report and request ID. This is a known issue on our side, specific to using Fable 5 through AWS Bedrock - it’s not your AWS setup or data retention config. We’re aware of it.

In the meantime you can keep using Fable 5 through Cursor’s standard model picker (with Bedrock toggled off for those requests), and continue using Bedrock for the models that work today: Opus, Sonnet, and Haiku.

A few others have hit the same thing in this thread - worth following there for updates.