Sigrid Jin relayed an adamantium Discord field report: Anthropic rejected requests with invalid_request_error when messages contained tool_use ids without immediately following tool_result blocks.
Coalesce consecutive tool-result messages after assistant tool_use blocks into one Anthropic user message, and drop orphan tool_use/tool_result blocks before dispatch so resume/edit/compaction boundary damage cannot reach the provider as a 400.
Tests cover parallel tool results and orphaned resume-boundary history.
Add ROADMAP pinpoint #255 summarizing the safe subset of hikaMaeng/Sigrid Jin's web-search provider work to adopt later.\n\nReviewed fork commits 262405e, bd11289, fa93cd3, 5f2540a, 7f34d91, and 535be97 from https://github.com/hikaMaeng/claw-code. This deliberately preserves attribution and avoids a blind cherry-pick because the cross-crate provider/spec/config/banner changes need a dedicated implementation lane with tests.