World's Fair 2026
Stop AI Agent Hallucinations: 5 Techniques + Production Patterns - Elizabeth Fuentes, AWS
Overview
This talk presents five techniques for reducing AI agent hallucinations and token waste, focusing on code-based solutions rather than prompt engineering. These methods aim to improve accuracy and catch failures before they impact users. The techniques include semantic tool selection, graph retrieval augmented generation (RAG), multi-agent validation, neuro-symbolic guardians, and runtime guardians.
Who should watch
- AI engineers and developers building agentic applications.
- Product managers seeking to improve the reliability of AI features.
- Builders looking for practical patterns to reduce costs and enhance AI accuracy.
- Anyone experiencing issues with AI agents providing incorrect or hallucinated responses.
Key takeaways
- Semantic tool selection filters the tools an agent can access for a specific query, significantly reducing token usage by only providing relevant tool descriptions.
- Graph RAG, using knowledge graphs like Neo4j, provides computed, verifiable answers for aggregation and multi-hop reasoning queries, unlike traditional text-based RAG which may sample or estimate.
- Multi-agent validation employs a sequence of agents (executor, validator, critic) to review and approve or reject responses, preventing agents from surfacing erroneous outputs.
- Neuro-symbolic guardians enforce rules directly in code (e.g., using Strands agent hooks) rather than relying on prompts, ensuring agents cannot bypass critical constraints.
- Runtime guardians, like those in the Agent Control library, allow for softer steering of agent behavior, enabling self-correction and task completion without hard stops, and rules can be updated dynamically without redeploying agent code.
- Productionizing these techniques can be achieved using services like Amazon Bedrock Agent Core, which offers managed infrastructure for agent execution, memory, and observability.
- Each technique demonstrated is available as code in a repository, allowing users to replicate the demos and adapt them for production.
Notable quotes
*Each one is a code change, not a prompt change.*
*The model sees only what it needs for that specific query.*
*The model gets a compute a verifiable answer, not a sample.*
Unofficial community note. Prefer the recording for nuance.