API to discover/list MCP servers behind a gateway

[onmete]

Feature Request: API to discover/list MCP servers behind a gateway

Use Case

OpenShift Lightspeed (OLS) is an AI-powered assistant that will integrate with MCP Gateway. As an MCP client, OLS needs to:

1. Discover available MCP servers behind the gateway
2. Expose this list to administrators/users so they can select which MCPs should be available to the assistant
3. Connect to a subset of MCPs relevant to the OLS use case (not all MCPs behind the gateway)

Problem

Currently, discovering MCP servers behind a gateway requires access to MCPServerRegistration resources and scanning/following them manually. This is not ideal for clients that need programmatic discovery.

Proposed Solution

Provide an API or mechanism for MCP clients to:

• List all MCP servers registered with a gateway
• Retrieve metadata about each MCP server (name, available tools, description)
• Optionally filter by virtual server or other criteria

Context

In a multi-tenant environment where multiple teams register their MCP servers with a shared gateway, clients like OLS need to:

• Know what's available
• Allow users to configure which MCPs are relevant to their use case
• Avoid receiving tools from irrelevant MCPs

This ties into the virtual MCP server concept and the X-Mcp-Virtualserver header mechanism.

[david-martin]

Dropping some initial thoughts here.

Related to #433

I was thinking would tool annotations help here, like an annotation with the original MCP Server name.
However, there's no built in way to the MCP protocol to search or filter based on annotation. It's just a tools list, with optional pagination/cursor. So that feels very limiting and would require client side filtering.

A built in mechanism to the protocol could help (discussed somewhat in #433).

Another approach is a new API, as suggested in the description above.

Question @onmete Is there a need for a more dynamic 'virtual' tool list than the existing MCPVirtualServer functionality?
As in, one that works via the HTTP API (like more headers or different endpoints) rather than via CRDs?
Or am I misunderstanding the ask?

[onmete]

This is the flow I have in my head:

1. OLS calls GET /mcp/servers → gets list of available servers
2. OLS exposes list to admin in OLSConfig
3. Admin selects: openshift-mcp, insights-mcp, ...
4. OLS creates MCPVirtualServer:
   spec:
     toolPrefixes:
       - openshift_
       - insights_
5. OLS uses X-Mcp-Virtualserver: openshift-lightspeed/ols-servers
6. Server adds new tools → automatically included (no update needed)

I'm operating on assumption that not all mcp servers behind gateway are relevant to specific clients, hence the need of choosing.

Another way around is to do this selection by gateway admin:

1. Gateway admin registers MCP servers (MCPServerRegistration)/selects through the MCP catalog
2. Gateway admin creates MCPVirtualServer "ols-production" with relevant mcp servers
3. OLS admin configures: "use ols-production virtual server"
4. OLS uses X-Mcp-Virtualserver: mcp-system/ols-production