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Registry Server scales up, vMCP gains observability

This week, we focused on operational readiness and flexibility: the Registry Server now auto-discovers server types and scales sync across multiple registry instances, Virtual MCP Server (vMCP) gained OpenTelemetry observability and smarter composite tools, and both the CLI and UI now fully support the ToolHive Registry Server.

ToolHive Registry Server: Smarter discovery and scalable sync​

The Registry Server now features improved auto-discovery capabilities and sync architecture. You can now:

  • Automatically detect whether an auto-registered server is an MCPServer, VirtualMCPServer, or MCPRemoteProxy.
  • Scale sync jobs across multiple registry instances with an improved sync implementation.
  • Deploy without hardcoded namespaces; the registry server now auto-discovers its operating namespace.
  • Connect the ToolHive CLI and UI to your Registry Server, bringing effortless discovery and deployment to your custom registry.

Virtual MCP Server: Observability and composite tool improvements​

vMCP gained production-grade observability and extended composite tool capabilities.

You can now:

  • Expose OpenTelemetry metrics on the standard Prometheus /metrics endpoint (request counts, latencies, backend health, active connections) and export distributed traces for backend client and workflow calls, enabling comprehensive monitoring, alerting, and debugging.
  • Define default results for skippable composite tool steps, ensuring workflows behave predictably across all conditional branches.
  • Use non-string arguments in composite tools, enabling structured output references for conditional logic, downstream step arguments, and final outputs.
  • Include MCPRemoteProxy resources in MCPGroups, allowing remote MCP servers to aggregate alongside local servers in your VirtualMCPServer configuration.

Getting started​

For detailed release notes, check the project repositories:

You can find all ToolHive documentation on the ToolHive documentation site.