[Bug] Anthropic API Error: Invalid or Inaccessible Model Configuration

Bug Description
Mid sessions doing mundane things: ⏺ There's an issue with the selected model (claude-fable-5[1m]). It may not exist or you may not have access to it. Run /model to pick a different model.

Environment Info

• Platform: darwin
• Terminal: Apple_Terminal
• Version: 2.1.170
• Feedback ID: c568115d-7684-442d-9b3d-7d833579ea4a

Errors

[{"error":"Error: 404 {\"type\":\"error\",\"error\":{\"type\":\"not_found_error\",\"message\":\"Claude Fable 5 is not available. Please use Opus 4.8. Learn more: https://www.anthropic.com/news/fable-mythos-access\"},\"request_id\":\"req_011CbzSXVziqF7GuxBimtu7k\"}\n    at generate (/$bunfs/root/src/entrypoints/cli.js:11:68217)\n    at makeRequest (/$bunfs/root/src/entrypoints/cli.js:51:7694)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-06-13T02:06:11.370Z"},{"error":"Error: 404 {\"type\":\"error\",\"error\":{\"type\":\"not_found_error\",\"message\":\"Claude Fable 5 is not available. Please use Opus 4.8. Learn more: https://www.anthropic.com/news/fable-mythos-access\"},\"request_id\":\"req_011CbzSaoay8KhR4HkuhPRTr\"}\n    at generate (/$bunfs/root/src/entrypoints/cli.js:11:68217)\n    at makeRequest (/$bunfs/root/src/entrypoints/cli.js:51:7694)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-06-13T02:06:56.114Z"}]