OpenAI ships a Messages plugin that summarises who you talk to and what about

OpenAI released a Mac-only Messages plugin for the ChatGPT desktop app that can read iMessage, SMS and RCS histories, search them, draft replies and, uniquely, generate summaries of contacts and conversation topics. Outgoing messages require explicit user approval by default, though a documented defect can bypass the prompt, and the service processes conversation data locally before sending summary results to OpenAI’s models.