Preview web apps live as your coding agent builds them with Amazon Bedrock AgentCore runtime

Judgment

Platform security owners, not each coding-agent user, should own AgentCore's default allowed-port list: tightening it narrows an authenticated ingress that forwards arbitrary HTTP and WebSocket traffic, but every blocked port turns a live Vite preview into an exception request.

Basis

Sundar Raghavan's AWS post says AgentCore runtime isolates each agent session in its own microVM and gives it a session endpoint—an authenticated URL that forwards each request's HTTP method, path, query string, body, and WebSocket connections to the ports the team allows. That design makes live Vite review fast because the app stays where the agent edits it, but the security boundary is not the browser URL alone: the endpoint is a general forwarder into the session, so the allowlist determines how much ingress the app exposes. The source gives no port count or default list, so the control point is the platform team's policy, with app teams requesting specific ports.