Agent failures with "classifyHandoffIfNeeded is not defined"

Bug Report

Version

claude-code 2.1.30

Description

Multiple agents spawned via the Task tool fail with the error classifyHandoffIfNeeded is not defined. The agents complete their work (tool calls, analysis) but fail at the final step when attempting to return results.

Steps to Reproduce

1. Launch multiple code-reviewer agents in parallel using the Task tool
2. Wait for agents to complete their analysis
3. Agents fail with classifyHandoffIfNeeded is not defined error

Expected Behavior

Agents should complete and return their results successfully.

Actual Behavior

Agents perform 30-60 tool calls, generate complete analysis, then fail with:

error: classifyHandoffIfNeeded is not defined

The full analysis is visible in the output file, suggesting the work completed but the return/handoff mechanism failed.

Frequency

5 out of 6 agent launches failed with this error in a single session.

Environment

• OS: macOS Darwin 25.2.0
• claude-code version: 2.1.30
• Model: claude-opus-4-5-20251101
• Agent type: code-reviewer