[Bug] Anthropic API Error: invalid_request_error when approaching context window limit

Bug Description
Hitting invalid_request_error when agent task nears context window

Environment Info

• Platform: darwin
• Terminal: ghostty
• Version: 2.1.44
• Feedback ID: 6146cd21-f2e2-47a2-9528-a111c26f06e2

Errors

[{"error":"Error: Tool mcp__plugin_episodic-memory_episodic-memory__search not found\n    at PRB (/$bunfs/root/claude:2105:7925)\n    at v7 (/$bunfs/root/claude:682:20801)\n    at F4 (/$bunfs/root/claude:682:39204)\n    at np (/$bunfs/root/claude:682:49829)\n    at cv (/$bunfs/root/claude:682:86106)\n    at dTT (/$bunfs/root/claude:682:85078)\n    at Al (/$bunfs/root/claude:682:84902)\n    at tp (/$bunfs/root/claude:682:81320)\n    at PR (/$bunfs/root/claude:682:6289)\n    at W8A (/$bunfs/root/claude:675:14001)","timestamp":"2026-02-17T14:42:35.107Z"},{"error":"Error: Tool mcp__plugin_episodic-memory_episodic-memory__read not found\n    at PRB (/$bunfs/root/claude:2105:7925)\n    at v7 (/$bunfs/root/claude:682:20801)\n    at F4 (/$bunfs/root/claude:682:39204)\n    at np (/$bunfs/root/claude:682:49829)\n    at cv (/$bunfs/root/claude:682:86106)\n    at dTT (/$bunfs/root/claude:682:85078)\n    at Al (/$bunfs/root/claude:682:84902)\n    at tp (/$bunfs/root/claude:682:81320)\n    at PR (/$bunfs/root/claude:682:6289)\n    at W8A (/$bunfs/root/claude:675:14001)","timestamp":"2026-02-17T14:42:35.108Z"},{"error":"Error: Tool mcp__plugin_episodic-memory_episodic-memory__read not found\n    at PRB (/$bunfs/root/claude:2105:7925)\n    at v7 (/$bunfs/root/claude:682:20801)\n    at F4 (/$bunfs/root/claude:682:39204)\n    at np (/$bunfs/root/claude:682:49829)\n    at cv (/$bunfs/root/claude:682:86106)\n    at dTT (/$bunfs/root/claude:682:85078)\n    at Al (/$bunfs/root/claude:682:84902)\n    at tp (/$bunfs/root/claude:682:81320)\n    at PR (/$bunfs/root/claude:682:6289)\n    at W8A (/$bunfs/root/claude:675:14001)","timestamp":"2026-02-17T14:42:35.110Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.31.content.1: `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_011CYDpPPjgwKHj4dUHYvRhx\"}\n    at generate (/$bunfs/root/claude:327:8796)\n    at makeRequest (/$bunfs/root/claude:366:5435)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-17T14:42:44.308Z"},{"error":"Error: API Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.31.content.1: `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_011CYDpPPjgwKHj4dUHYvRhx\"}\n    at bET (/$bunfs/root/claude:3159:795)\n    at async hyB (/$bunfs/root/claude:3244:2545)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-17T14:42:44.310Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.31.content.1: `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_011CYDpPUWS7WR6Les5xNFPj\"}\n    at generate (/$bunfs/root/claude:327:8796)\n    at makeRequest (/$bunfs/root/claude:366:5435)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-02-17T14:42:45.711Z"}]