# AWS shows how to enforce per-user access in an agent's knowledge base search

> Original title: Fine-grained access control for Amazon Bedrock Managed Knowledge Base tools

- Source: AWS Machine Learning Blog
- Published: 2026-11-12T15:40:24.000Z
- Bad Influence: https://badinfluence.news/items/wofib183kzc6cg45uccy8puqo
- Original: https://aws.amazon.com/blogs/machine-learning/fine-grained-access-control-for-amazon-bedrock-managed-knowledge-base-tools/

## Summary

AWS explains how to limit an agent's searches on Amazon Bedrock Managed Knowledge Base to the documents each user may view. The design has a request interceptor inject userContext from the verified token, with Policy in AgentCore and a resource-based policy as secondary defenses, so the LLM does not set user identity.

## Why it matters

The post shows why an LLM must not supply the user identity for a knowledge base search, and how deterministic injection plus a policy check and a resource-based deny enforce per-user access.