[Feature] Stop Agent Follow-up Actions After Tool Failures

[houko]

Description

Stop agent follow-up actions after tool failures to prevent cascading errors.

OpenFang Reference

• Original Issue: Stop agent follow-up actions after tool failures RightNow-AI/openfang#424

Test Plan

• Follow-up actions stop on tool failure
• Error handling works correctly

[houko]

Closing as duplicate of #309.