After dissecting Claude Code's 18+ caching mechanisms, I found that you can't touch provider-level prompt cache, but embedding cache, tool result cache, and entity cache are not only within your reach — they deliver even better results. Includes a complete AgentCache interface design and per-tool TTL strategy.
Every one of Claude Code's 45 tools uses a prompt() method that dynamically adjusts based on user type, feature flags, and system capabilities. Applying this pattern to a ReAct Agent, tool descriptions are dynamically generated along three dimensions: orchestrator model capability, locale, and available tools. Small models automatically get few-shot examples; large models save tokens.
An AI agent is not a black box — it is built from three layers: what it knows (Context), how it thinks (Cognition), and what it can do (Action). Understanding these three layers is the key to grasping why agents are sometimes brilliant and sometimes go off the rails, and how to design a truly effective agent system.