MCP Gateway 0.6: Tech Preview Release

  • By: David Martin |

The MCP Gateway has reached its 0.6 tech preview release. This release adds a Kubernetes operator, MCP specification elicitation support, and Redis-backed horizontal scaling. For the full list of changes you can check out the 0.6.0 release page on GitHub.

For background on the MCP Gateway, see the previous 0.5 dev preview announcement or the overview documentation.

From Dev Preview to Tech Preview

The 0.5 release was a dev preview, a first look at the core MCP Gateway functionality. With 0.6, the project moves to a tech preview as we work toward production readiness. APIs and interfaces may still change, but the foundations are now in place:

What's New in 0.6

Kubernetes Operator and MCPGatewayExtension CRD

The 0.6 release adds an OLM-based installation alongside the existing Helm chart approach. The operator introduces the MCPGatewayExtension custom resource for configuring the MCP Gateway.

An MCPGatewayExtension targets a Gateway listener and configures the MCP routing layer:

apiVersion: mcp.kuadrant.io/v1alpha1
kind: MCPGatewayExtension
metadata:
  name: mcp-gateway
spec:
  targetRef:
    group: gateway.networking.k8s.io
    kind: Gateway
    name: mcp-gateway
    namespace: gateway-system
    sectionName: mcp

The operator manages the MCP Router and Broker components, and (optionally) automatically creates HTTPRoute resources based on the MCPGatewayExtension configuration. Manual route definition is no longer needed.

See the OLM install guide to get started.

MCP Specification Elicitation Support

This release adds support for the MCP protocol's elicitation capability. Elicitation allows an MCP server to request additional information from the client during a tool call, enabling multi-turn exchanges between the agent and server. Below is a sequence diagram showing how elicitation events are mapped at the gateway between the client and server. Note the different request IDs on either side of the gateway, as the gateway abstracts this from the client.

sequenceDiagram
  participant Client as MCP Client
  participant Gateway as Gateway/MCP Router/MCP Broker
  participant Server as MCP Server

  Note over Client, Server: Tool call with elicitation
  Client ->> Gateway: POST /mcp "tools/call"
  Gateway ->> Server: POST /mcp "tools/call"
  Note over Server, Gateway: Elicitation event
  Server -->> Gateway: Streamed event: elicitation/create (id: 42)
  Gateway ->> Gateway: Map server request ID (42) to gateway request ID (gateway-123)
  Gateway -->> Client: Streamed event: elicitation/create (id: gateway-123)
  Note over Client: User provides input
  Client ->> Gateway: POST /mcp elicitation response (id: gateway-123)
  Gateway ->> Gateway: Map gateway request ID (gateway-123) to server request ID (42)
  Gateway ->> Server: POST /mcp elicitation response (id: 42)
  Note over Server, Gateway: Tool call continues/resumes
  Server -->> Gateway: tool/call response
  Gateway -->> Client: tool/call response

As the MCP specification evolves, the MCP Gateway will continue to align its feature support with the spec. Teams adopting the gateway should not need to worry about protocol-level compatibility.

Redis Session Store for Horizontal Scaling

The release also introduces a Redis-backed session store for horizontal scaling. When the MCP Gateway aggregates multiple MCP servers behind a single endpoint, it maintains session ID mappings between client sessions and upstream servers. The session store moves these mappings into Redis so that multiple gateway replicas can share state, removing the single-instance constraint from the dev preview.

Configure it via the sessionStore field in the MCPGatewayExtension spec:

apiVersion: mcp.kuadrant.io/v1alpha1
kind: MCPGatewayExtension
metadata:
  name: mcp-gateway
spec:
  targetRef:
    group: gateway.networking.k8s.io
    kind: Gateway
    name: mcp-gateway
    namespace: gateway-system
    sectionName: mcp
  sessionStore:
    secretName: redis-credentials

With a session store configured, requests can be load-balanced across replicas without session affinity.

What's Next

There will likely be additional releases before the MCP Gateway reaches GA with a 1.0. The 0.7 milestone includes a review of the virtual server API, tool search and discovery, and an investigation into how A2A fits into the picture, among other items.

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