[Bug] Anthropic API Error: Cannot modify thinking/redacted_thinking blocks in assistant messages

Bug Description
Sessions keep crashing with this 400 API error about thinking/redacted thinking blocks must not be modified: API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.7.content.177: thinking or redacted_thinking blocks in the latest assistant message cannot be modified. These blocks must remain as they were in the original
response."},"request_id":"req_011CXjCuTVhjqkYd6sPmgwd5"}

Environment Info

• Platform: darwin
• Terminal: Apple_Terminal
• Version: 2.1.29
• Feedback ID: b6ecf632-d84a-4276-a67f-314592279d91

Errors

[{"error":"Error: Request was aborted.\n    at i5R (/$bunfs/root/claude:1522:23441)\n    at vpB (/$bunfs/root/claude:4717:7450)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-02T09:24:50.535Z"},{"error":"TelemetrySafeError: Argument Validation Error\n    at BfB (/$bunfs/root/claude:3220:35173)\n    at async call (/$bunfs/root/claude:3220:49994)\n    at async KD8 (/$bunfs/root/claude:3059:12903)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-02T09:26:37.261Z"},{"error":"Error: 1P event logging: 26 events failed to export (code=ECONNABORTED, timeout of 10000ms exceeded)\n    at queueFailedEvents (/$bunfs/root/claude:202:2350)\n    at async doExport (/$bunfs/root/claude:202:1257)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-02T11:34:14.024Z"},{"error":"Error: {\"message\":\"Failed to export 26 events (code=ECONNABORTED, timeout of 10000ms exceeded)\",\"originalLine\":\"202\",\"originalColumn\":\"1409\",\"line\":\"202\",\"column\":\"1409\",\"sourceURL\":\"/$bunfs/root/claude\",\"stack\":\"Error: Failed to export 26 events (code=ECONNABORTED, timeout of 10000ms exceeded)\\n    at doExport (/$bunfs/root/claude:202:1409)\\n    at processTicksAndRejections (native:7:39)\",\"name\":\"Error\"}\n    at error (/$bunfs/root/claude:1722:25028)\n    at <anonymous> (/$bunfs/root/claude:188:42062)\n    at ZZD (/$bunfs/root/claude:188:42606)\n    at <anonymous> (/$bunfs/root/claude:189:17366)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-02T11:34:14.025Z"},{"error":"Error: ensureToolResultPairing: repaired missing tool_result blocks (258 -> 266 messages). Message structure: [0] user; [1] assistant(id=msg_015yJyMC2UgaJ9bnTYrv9xxt, tool_uses=[toolu_01PGbxjiESCQjbGdhYan9DCi]); [2] user(tool_results=[toolu_01PGbxjiESCQjbGdhYan9DCi]); [3] assistant(id=msg_014y9xkdQhCZHfrdeg1B9fq9, tool_uses=[toolu_01MojGxsQEN78TKjq3eJm3z9]); [4] user(tool_results=[toolu_01MojGxsQEN78TKjq3eJm3z9]); [5] assistant(id=msg_01GWweJtt6LiBBCssxT4hjSW, tool_uses=[toolu_01BD47Xht1fW97Grnjux94Qw]); [6] user(tool_results=[toolu_01BD47Xht1fW97Grnjux94Qw]); [7] assistant(id=msg_01Mb2BcGXL4m9mdFeJEcWVfy, tool_uses=[toolu_01DkzhtHSACFhpCrTvk1BtNv]); [8] user(tool_results=[toolu_01DkzhtHSACFhpCrTvk1BtNv]); [9] assistant(id=msg_017dVdi3bGVSYCJ9roJrU36H, tool_uses=[toolu_01G6KpgkR1tikGjxYkFcP7Ge]); [10] user(tool_results=[toolu_01G6KpgkR1tikGjxYkFcP7Ge]); [11] assistant(id=msg_011hKYtgXUz4JSN1eYQXZt6G, tool_uses=[toolu_01GX1dVpsXpfNpSbUPpyHEGn]); [12] user(tool_results=[toolu_01GX1dVpsXpfNpSbUPpyHEGn]); [13] assistant(id=msg_01Tgdh8iPKmUcbdJn6nswMFA, tool_uses=[toolu_01YB8aB5ZHsQF9kSjtBYW5fQ]); [14] user(tool_results=[toolu_01YB8aB5ZHsQF9kSjtBYW5fQ]); [15] assistant(id=msg_013jiQ3LYrddko1Pqfz3i8CB, tool_uses=[toolu_01F2AmzSsMVKPFzHC9bZNfSU]); [16] user(tool_results=[toolu_01F2AmzSsMVKPFzHC9bZNfSU]); [17] assistant(id=msg_01Xptce7AqTWtJCp2QFGujfU, tool_uses=[toolu_01K25udtWTK9UCXE1r7kZv8F]); [18] user(tool_results=[toolu_01K25udtWTK9UCXE1r7kZv8F]); [19] assistant(id=msg_01Rv2pdWML8EUCVngwFVw5BE, tool_uses=[toolu_01GQw8YMC6Ms2CrhdLvggPpA]); [20] user(tool_results=[toolu_01GQw8YMC6Ms2CrhdLvggPpA]); [21] assistant(id=msg_01F7KVmZLy8b3hzwBJ9BW9N9, tool_uses=[toolu_01T1YYJEMEwQ6ifbreU9S3bH]); [22] user(tool_results=[toolu_01T1YYJEMEwQ6ifbreU9S3bH]); [23] assistant(id=msg_016tYQiVPjCHvawgJi7kh6vQ, tool_uses=[toolu_018BK3aRUJUR2SYAgJEcQWGn]); [24] user(tool_results=[toolu_018BK3aRUJUR2SYAgJEcQWGn]); [25] assistant(id=msg_01PrvoJemzBXK8sk8dCySoGB, tool_uses=[]); [26] user; [27] assistant(id=msg_01DfJvVFz4BfLG37dD8CgXdi, tool_uses=[toolu_01CQqWqv1ozq26SgHVprhS7V]); [28] user(tool_results=[toolu_01CQqWqv1ozq26SgHVprhS7V]); [29] assistant(id=msg_01RpgfikuckXLG1nenDNiF24, tool_uses=[toolu_01KaMAYWmXSZTPBHuEgNfvFK]); [30] user(tool_results=[toolu_01KaMAYWmXSZTPBHuEgNfvFK]); [31] assistant(id=msg_01CBu1Yp18sLeFU3YKEVnfnV, tool_uses=[toolu_016YqPfXoCoHzvfeXAEnHfvS]); [32] user(tool_results=[toolu_016YqPfXoCoHzvfeXAEnHfvS]); [33] assistant(id=msg_016QtaQ6hGshmBiFern8vxsn, tool_uses=[toolu_01NHfss4kRAZCWS8HvqhZwUr]); [34] user(tool_results=[toolu_01NHfss4kRAZCWS8HvqhZwUr]); [35] assistant(id=msg_01HgC8DGxsm6dR54VZ8MDNYT, tool_uses=[toolu_01MnqkdnzaKEpHcYTb63WmTX]); [36] user(tool_results=[toolu_01MnqkdnzaKEpHcYTb63WmTX]); [37] assistant(id=msg_01EEsNd99M6f2epBVX9G7yFX, tool_uses=[toolu_01W88imaisX9TKwcSwrNbJyu]); [38] user(tool_results=[toolu_01W88imaisX9TK…

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