Enable cross-session Claude prompt caching

What changed

Hermes Agent added cross-session prompt caching for Claude models. System prompts, skills, and memory now stay cached for one hour across separate sessions. The update targets latency and token costs during restarts or background memory checks.

The change applies automatically when users select Claude through the /model command or OpenRouter routes. No extra configuration is required beyond existing Claude API keys.

Why it matters

Persistent memory in Hermes Agent becomes cheaper to maintain over time. Vibe Builders who run background reviews or restart chats frequently will see lower bills and faster responses.

This move strengthens Hermes Agent against hosted alternatives that charge per session. It bets on users keeping long-running agents alive on cheap VPS hardware rather than paying SaaS premiums.

How to use it

Update to the latest Hermes Agent release via the built-in /update command. Switch to any Claude model with /model claude-3-5-sonnet or similar. Start a new session and confirm caching works by checking reduced token counts on repeat prompts.

Access the local web dashboard with hermes web to monitor cache hits during memory reviews. The feature is live now for all self-hosted installs using Anthropic keys.

Watch for

Confirm the bet by tracking actual token savings over a full week of mixed sessions. The feature breaks if cache invalidation happens too often or if Claude rate limits ignore the saved context. Expect a follow-up move toward longer cache windows or support for additional models.