Show HN: Claude-thermos – keeps your Claude session warm for you

Claude-thermos is a tool that prevents Claude Code's prompt cache from expiring during long sessions, saving approximately 20% on API costs. The cache expires after 5 minutes of inactivity, which commonly occurs when the main agent waits for subagents to complete tasks, forcing expensive re-encoding of the entire conversation history. Users can run claude-thermos as a wrapper around the Claude CLI to automatically keep the cache warm in the background with configurable timing parameters.