[Bug] Anthropic API Error: Incompatible model for tool advisor when using claude-fable-5

Found 2 possible duplicate issues:

1. https://github.com/anthropics/claude-code/issues/66614
2. https://github.com/anthropics/claude-code/issues/66714

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🤖 Generated with Claude Code

Bug Description just getting this message on repeat since upgrading: Fable 5 is here! Our newest model for complex, long-running work ▎ Included in your plan limits until Jun 22, then switch to usage credits to continue. ❯ what worktrees do we have locally ⏺ API Error: 400 tools.10.model: 'claude-opus-4-8' cannot be used as an advisor when the request model is 'claude-fable-5'. Environment Info Platform: darwin Terminal: iTerm.app Version: 2.1.170 Feedback ID: 7945f31e-74f9-465a-b9cd-8d217cdf1b41 Errors [{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"tools.10.model: 'claude-opus-4-8' cannot be used as an advisor when the request model is 'claude-fable-5'.\"},\"request_id\":\"req_011CbtgQnjCkaXnj6ii1dDzB\"}\n at generate (/$bunfs/root/src/entrypoints/cli.js:11:68106)\n at makeRequest (/$bunfs/root/src/entrypoints/cli.js:51:7694)\n at processTicksAndRejections (native:7:39)","timestamp":"2026-06-10T01:04:41.934Z"}]

Same for me.

same for me

I think this is documented An Opus or Sonnet advisor is rejected when main model is Fable.
https://code.claude.com/docs/en/advisor
Maybe you have set your advisor model to Opus somewhere else?

Removing the advisor solved it for me, which makes sense actually. :)

same

You just need to remove the advisor in the /advisor menu

Same here, how to disable the advisor in VSCode extension ? /advisor is not a valid command in vscode extension (and the advisor is already disabled in the claude code CLI)

Same here. Temporarily removed the /advisor option as fallback mechanism.

Same here, how to disable the advisor in VSCode extension ? /advisor is not a valid command in vscode extension (and the advisor is already disabled in the claude code CLI)

@kreare Maybe you need to checkout ~/.claude/settings.json or your current folder .claude/settings.json to see if there is an advisor entry.

Advisor is a config available in Claude code.
It is not available on Claude Desktop.

In case someone is coming from the Desktop first - like myself.

check screenshot by @tkanov

@kreare maybe this could help you.

Closing for now — inactive for too long. Please open a new issue if this is still relevant.