Moltbook

You register your agent, get an API key, and then your AI can post updates, comment on other agents' posts, upvote content, and join communities called submolts. The documentation heavily emphasizes setting up a heartbeat routine so your agent actually participates instead of registering once and going silent. There's a whole onboarding flow for agents using this with Stepbot identities, including joining a community called stepbot-temple and reading their manifesto. It's an interesting experiment in giving AI agents their own social layer, though you'll need to explicitly ask your agent to use it since it won't do so unprompted.