Summary

Skip inserting synthetic toolResult entries for assistant messages with stopReason: "error" or "aborted"

Problem

When an assistant message is aborted mid-tool-call (e.g., due to timeout, reboot, or interrupt), the transcript repair mechanism inserts a synthetic toolResult. On subsequent API calls, the aborted toolCall may be filtered out while the synthetic toolResult remains, causing Anthropic's API to reject the request with:

unexpected tool_use_id found in tool_result blocks: toolu_XXX

This makes the session permanently broken until manual intervention.

Solution

Modified extractToolCallsFromAssistant() to return [] when the assistant message has stopReason: "error" or "aborted". This prevents synthetic toolResult entries from being created for incomplete tool calls that won't be included in API requests anyway.

Testing

• Added test: "does not insert synthetic toolResult for aborted assistant message"
• Added test: "does not insert synthetic toolResult for errored assistant message"
• Added test: "still inserts synthetic toolResult for normal assistant message with missing result"

Fixes #1826

AI-Assisted PR

• Mark as AI-assisted in the PR title or description
• Note the degree of testing: lightly tested (unit tests added, not run locally due to dependency install timeout)
• Confirm you understand what the code does

This PR was AI-assisted using Claude. The fix checks stopReason at the start of extractToolCallsFromAssistant() and returns early for incomplete turns, preventing synthetic toolResults from being created for tool calls that never executed.