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Improve bot accuracy with Amazon Lex Assisted NLU

Machine Learning Blog



This article explains how to improve Amazon Lex bot accuracy using Assisted NLU, which leverages large language models to handle natural language variations without manual configuration.

  • Assisted NLU uses LLMs for intent classification and slot resolution, achieving 92% intent accuracy and 84% slot accuracy
  • Two operating modes: Primary (LLM processes all inputs) and Fallback (LLM only when confidence is low)
  • Craft intent descriptions following pattern: "Intent to [action verb] [object] [context]"
  • Write precise slot descriptions specifying what is captured, contextual constraints, and valid value guidance
  • Use Test Workbench to validate configuration against edge cases, typos, and colloquial expressions
  • Monitor fulfilledByAssistedNlu metric to determine optimal operating mode
  • Implement safe rollout using versioning, aliases, and A/B testing before production deployment
  • Enable conversation logs and CloudWatch monitoring to track real-world performance metrics

Assisted NLU is included at no additional cost and helps bots handle real customer communication patterns, reducing fallback responses and improving user satisfaction.



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