People need to talk to agents. That does not make the conversation the product. The product is which agent takes the task, which tools it may use, what it retrieved, and whether a person had to finish the job. Hide that, and you have a demo. Show it, and you have an interface to a system.
Chat is Linear Horizon’s full-page interface to Platform: streaming answers, a picker for the right agent, a view of tool calls and sub-agents, and optional voice. The browser talks to one origin. Sign-in and permissions apply as they should.
If you only need a box on a page, you do not need this case. If you need people to work with an agent system they can inspect, start with Chat on Platform — or with consulting if the runtime is not yet decided.