This is close to a lot of what's happening at Glue. Threads are first-class, so you can start a thread within a group - let's talk about our GraphQL schema and that thread should live in the API Development group. You can also start a thread without a group - just me and another 2 coworkers need to discuss a specific point that would be noisy for everybody else.
Glue AI can be invoked at any time in any context and you can choose whether or not you want to share your conversation with other people after the fact. MCP is also well supported so you get good integration with lots of services like Linear or Notion.
The agent isn't quite as proactive as updating documentation without being prompted right now, but it's regularly done by telling Glue AI to update pages in Notion with info from a thread.