As a platform engineer, I want the gateway to dynamically discover and register MCP Servers and configure Istio/Envoy clusters and routing rules, so that I can expose tools from multiple backends via a unified MCP Gateway.

Considerations:

• Support static config and dynamic registration (e.g. via CRs or service discovery)
• For each MCP server, update Istio/Envoy with:
  • cluster config
  • routing rules (match on mcp server header)
• How does mcp server registration feed into the tools/list response?
• Avoid name collisions (e.g. prefix tool names by backend service name)
• Validate and log registration events for traceability
• Fail gracefully if a server becomes unreachable (without taking down the gateway)

For updating Istio/Envoy, some options are:

• Creating an EnvoyFilter resource
• Exposing an xDS server that updates config in Envoy
• creating a HTTPRoute(s) for mcp servers (which should in turn create entries in the Envoy config). This option has been explored internally somewhat and is worth evaluating first as it could avoid extra integration logic.