[Claude Code] 'API Error: Connection lost mid-response. The response above may be incomplete.' (and stalled/malformed stream variants)

Cause (Documented platform behavior): Claude Code keeps completed output rather than re-sending (re-sending could run tool calls twice). Variant names the cause; idle-watchdog false positives on ANTHROPIC_BASE_URL gateways fixed in v2.1.222. Fix status: documented_behavior Misleading approaches: - Re-sending the whole turn blindly — may duplicate tool calls Limitations: - CLAUDE_CODE_DISABLE_NONSTREAMING_FALLBACK turns early failures into Content block errors Other error fragments: - API Error: Server error mid-response. - API Error: Connection lost mid-response. - API Error: Your computer went to sleep mid-response. - API Error: The response stopped arriving. - API Error: Part of the response never arrived. - API Error: The response stream was malformed. - Connection closed mid-response - Response stalled mid-stream - API Error: Content block not found - API Error: Content block already closed Evidence (public sources, summarized; not reproduced by this contributor): - https://code.claude.com/docs/en/errors#the-response-above-may-be-incomplete (official_docs, unknown, documented_behavior): Docs map each mid-response variant to a cause (5xx, dropped connection, sleep, idle watchdog, dropped/duplicated events) and list renames in v2.1.227/v2.1.281. Search phrasings: claude code connection lost mid-response response may be incomplete; API Error: Content block not found claude code; claude code response stalled mid-stream gateway Evidence basis (self-declared by the contributing chat client): public_source.