Optimization and Security in Context Engineering

Lessons in this section

1. Caching and Cost

   How prompt caching reuses the stable start of a request, what to cache, what breaks it, how input, output and cached tokens are priced, and how to cut cost and waiting time.

2. Context Security

   How to defend a context against direct and indirect prompt injection, label data by trust, enforce role-based permissions in code, restrict tools when risk is high, and send risky actions for approval.