Credentials should never reach the model

What this post added

Introduces the concept of credential isolation as a security measure for agentic AI systems. It proposes a 'broker' pattern where a mediating service holds sensitive credentials and enforces access scope for agent requests, preventing raw credentials from entering the model process. This mitigates risks associated with prompt injection leading to credential exfiltration. The post also emphasizes the importance of controlling egress paths and failing closed to ensure the broker pattern is consistently applied.