[Bug] Claude Code ignores $TMPDIR environment variable, creates /tmp/claude with restrictive permissions

Bug Description
claude code doesn't respect the $TMPDIR env variable and creates a /tmp/claude with restrictive permissions creating issues on multi-user machines

Environment Info

• Platform: darwin
• Terminal: iTerm.app
• Version: 2.1.20
• Feedback ID: 8597440e-c8bf-4800-9d43-629560ceb60d

Errors

[{"error":"SyntaxError: JSON Parse error: Unexpected identifier \"API\"\n    at <parse> (:0)\n    at parse (unknown)\n    at <anonymous> (/$bunfs/root/claude:70:855)\n    at A (/$bunfs/root/claude:11:7259)\n    at tAB (/$bunfs/root/claude:1663:749)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-01-28T21:45:31.405Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"output_config: Extra inputs are not permitted\"},\"request_id\":\"req_011CXaWT26KWV827PGtWwd7i\"}\n    at generate (/$bunfs/root/claude:145:37631)\n    at makeRequest (/$bunfs/root/claude:162:5435)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-01-28T21:45:31.718Z"},{"error":"SyntaxError: JSON Parse error: Unexpected identifier \"API\"\n    at <parse> (:0)\n    at parse (unknown)\n    at <anonymous> (/$bunfs/root/claude:70:855)\n    at A (/$bunfs/root/claude:11:7259)\n    at Wt_ (/$bunfs/root/claude:1540:40110)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-01-28T21:45:31.719Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"output_config: Extra inputs are not permitted\"},\"request_id\":\"req_011CXaWgc6LABASGvyGMz7Ea\"}\n    at generate (/$bunfs/root/claude:145:37631)\n    at makeRequest (/$bunfs/root/claude:162:5435)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-01-28T21:48:35.928Z"},{"error":"SyntaxError: JSON Parse error: Unexpected identifier \"API\"\n    at <parse> (:0)\n    at parse (unknown)\n    at <anonymous> (/$bunfs/root/claude:70:855)\n    at A (/$bunfs/root/claude:11:7259)\n    at tAB (/$bunfs/root/claude:1663:749)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-01-28T21:48:35.928Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"output_config: Extra inputs are not permitted\"},\"request_id\":\"req_011CXaWgd3shLa3cJTra3U8R\"}\n    at generate (/$bunfs/root/claude:145:37631)\n    at makeRequest (/$bunfs/root/claude:162:5435)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-01-28T21:48:36.152Z"},{"error":"SyntaxError: JSON Parse error: Unexpected identifier \"API\"\n    at <parse> (:0)\n    at parse (unknown)\n    at <anonymous> (/$bunfs/root/claude:70:855)\n    at A (/$bunfs/root/claude:11:7259)\n    at Wt_ (/$bunfs/root/claude:1540:40110)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-01-28T21:48:36.152Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"output_config: Extra inputs are not permitted\"},\"request_id\":\"req_011CXaXAsHue72sGzxSLmYVH\"}\n    at generate (/$bunfs/root/claude:145:37631)\n    at makeRequest (/$bunfs/root/claude:162:5435)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-01-28T21:54:59.365Z"},{"error":"SyntaxError: JSON Parse error: Unexpected identifier \"API\"\n    at <parse> (:0)\n    at parse (unknown)\n    at <anonymous> (/$bunfs/root/claude:70:855)\n    at A (/$bunfs/root/claude:11:7259)\n    at tAB (/$bunfs/root/claude:1663:749)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-01-28T21:54:59.366Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"output_config: Extra inputs are not permitted\"},\"request_id\":\"req_011CXaXAtRsdqF95UkWKihv3\"}\n    at generate (/$bunfs/root/claude:145:37631)\n    at makeRequest (/$bunfs/root/claude:162:5435)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-01-28T21:54:59.560Z"},{"error":"SyntaxError: JSON Parse error: Unexpected identifier \"API\"\n    at <parse> (:0)\n    at parse (unknown)\n    at <anonymous> (/$bunfs/root/claude:70:855)\n    at A (/$bunfs/root/claude:11:7259)\n    at Wt_ (/$bunfs/root/claude:1540:40110)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-01-28T21:54:59.560Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"output_config: Extra inputs are not permitted\"},\"request_id\":\"req_…

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