[Bug] Anthropic API Error: 400 Bad Request with extended thinking enabled

Bug Description
constant 400s with modified thinking

Environment Info

• Platform: darwin
• Terminal: ghostty
• Version: 2.1.39
• Feedback ID: fd16d5ae-f56c-444a-9ffb-7eec4af1f16b

Errors

[{"error":"Error\n    at vk (/$bunfs/root/claude:42:1144)\n    at <anonymous> (/$bunfs/root/claude:43:10097)\n    at emit (node:events:92:22)\n    at endReadableNT (internal:streams/readable:861:50)\n    at processTicksAndRejections (native:7:39)\n    at request (/$bunfs/root/claude:45:2149)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-13T18:40:06.166Z"},{"error":"Error\n    at vk (/$bunfs/root/claude:42:1144)\n    at <anonymous> (/$bunfs/root/claude:43:10097)\n    at emit (node:events:92:22)\n    at endReadableNT (internal:streams/readable:861:50)\n    at processTicksAndRejections (native:7:39)\n    at request (/$bunfs/root/claude:45:2149)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-13T18:40:19.145Z"},{"error":"Error\n    at vk (/$bunfs/root/claude:42:1144)\n    at <anonymous> (/$bunfs/root/claude:43:10097)\n    at emit (node:events:92:22)\n    at endReadableNT (internal:streams/readable:861:50)\n    at processTicksAndRejections (native:7:39)\n    at request (/$bunfs/root/claude:45:2149)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-13T18:40:24.040Z"},{"error":"Error\n    at vk (/$bunfs/root/claude:42:1144)\n    at <anonymous> (/$bunfs/root/claude:43:10097)\n    at emit (node:events:92:22)\n    at endReadableNT (internal:streams/readable:861:50)\n    at processTicksAndRejections (native:7:39)\n    at request (/$bunfs/root/claude:45:2149)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-13T18:40:42.299Z"},{"error":"Error: Web search error: unavailable\n    at J48 (/$bunfs/root/claude:2239:2541)\n    at call (/$bunfs/root/claude:2239:6860)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-13T19:04:13.166Z"},{"error":"MaxFileReadTokenExceededError: File content (77582 tokens) exceeds maximum allowed tokens (25000). Please use offset and limit parameters to read specific portions of the file, or use the GrepTool to search for specific content.\n    at qPB (/$bunfs/root/claude:3292:3360)\n    at async call (/$bunfs/root/claude:3301:2475)\n    at async <anonymous> (/$bunfs/root/claude:5800:1669)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-13T19:09:31.366Z"},{"error":"MaxFileReadTokenExceededError: File content (77582 tokens) exceeds maximum allowed tokens (25000). Please use offset and limit parameters to read specific portions of the file, or use the GrepTool to search for specific content.\n    at qPB (/$bunfs/root/claude:3292:3360)\n    at async call (/$bunfs/root/claude:3301:2475)\n    at async <anonymous> (/$bunfs/root/claude:5800:1669)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-13T19:10:33.070Z"},{"error":"Error: Request was aborted.\n    at oGR (/$bunfs/root/claude:865:99149)\n    at next (native:1:11)\n    at ssB (/$bunfs/root/claude:5705:4480)\n    at next (native:1:11)\n    at esB (/$bunfs/root/claude:5710:7793)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-13T21:08:33.367Z"},{"error":"Error: EISDIR: illegal operation on a directory, read\n    at readFileSync (unknown)\n    at <anonymous> (/$bunfs/root/claude:12:742)\n    at B2 (/$bunfs/root/claude:11:49917)\n    at readFileSync (/$bunfs/root/claude:12:701)\n    at OPB (/$bunfs/root/claude:6130:18120)\n    at call (/$bunfs/root/claude:3301:2415)\n    at uW8 (/$bunfs/root/claude:3479:14100)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-13T21:10:46.388Z"},{"error":"MaxFileReadTokenExceededError: File content (37113 tokens) exceeds maximum allowed tokens (25000). Please use offset and limit parameters to read specific portions of the file, or use the GrepTool to search for specific content.\n    at qPB (/$bunfs/root/claude:3292:3360)\n    at async call (/$bunfs/root/claude:3301:2475)\n    at async <anonymous> (/$bunfs/root/claude:5800:1669)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-14T03:30:11.970Z"},{"error":"MaxFileReadTokenExceededError: File content (37113 tokens) exceeds maximum allowed tokens (25000). Please use offset and limit parameters to read specific portions of the file, or use the GrepTool to search for specific content.\n    at qPB (/$bunfs/root/claude:3292:3360)\n    at async call (/$bunfs/root/claude:3301:2475)\n    at async <anonymous> (/$bunfs/root/claude:5800:1669)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-14T03:30:17.073Z"},{"error":"MaxFileReadTokenExceededError: File content (37113 tokens) exceeds maximum a…

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