Three tiers: if your agent calls gpt-4o with the same prompt twice, the second call returns from Valkey in under 1ms instead of hitting the API. Same for tool calls - if your agent calls get_weather("Sofia") twice with the same arguments, the cached result comes back instantly. And session state (what step the agent is on, user intent, LangGraph checkpoints) persists across requests with per-field TTL.

The main difference from existing options is that LangChain's cache only handles LLM responses, LangGraph's checkpoint-redis only handles state (and requires Redis 8 + modules), and none of them ship OpenTelemetry or Prometheus instrumentation at the cache layer. This puts all three tiers behind one Valkey connection with observability built in.