[Bug] Anthropic API Error: Unsupported effort level 'xhigh' without thinking enabled

Bug Description
Web Search("Claude Code effortLevel high Opus 5 recommended setting")
⎿  Error: API Error: 400 output_config.effort 'xhigh' is not supported when thinking is disabled on this model. Use effort 'high' or below, or enable
thinking.

Environment Info

• Platform: darwin
• Terminal: iTerm.app
• Version: 2.1.220
• Feedback ID: 34423f4d-fa0d-4749-8156-26d6e28cf520

Errors

[{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"output_config.effort 'xhigh' is not supported when thinking is disabled on this model. Use effort 'high' or below, or enable thinking.\"},\"request_id\":\"req_011CdNP2tbAJHJEzxL14v7nu\"}\n    at generate (/$bunfs/root/src/entrypoints/cli.js:40:49836)\n    at makeRequest (/$bunfs/root/src/entrypoints/cli.js:80:7690)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-07-25T07:27:54.711Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"output_config.effort 'xhigh' is not supported when thinking is disabled on this model. Use effort 'high' or below, or enable thinking.\"},\"request_id\":\"req_011CdNQ5mWxjaApMZzSvgseU\"}\n    at generate (/$bunfs/root/src/entrypoints/cli.js:40:49836)\n    at makeRequest (/$bunfs/root/src/entrypoints/cli.js:80:7690)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-07-25T07:41:41.099Z"}]