Skip to content

MCP Gateway 0.6 blog post, inc mermaid plugin #89

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
david-martin merged 1 commit into from
Apr 20, 2026
Merged

MCP Gateway 0.6 blog post, inc mermaid plugin #89

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
13 changes: 13 additions & 0 deletions src/_includes/layout.njk
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -145,6 +145,19 @@ title: Kuadrant.io
<script src="https://cdnjs.cloudflare.com/ajax/libs/prism/1.29.0/components/prism-yaml.min.js"></script>


<script type="module">
import mermaid from 'https://cdn.jsdelivr.net/npm/mermaid@11/dist/mermaid.esm.min.mjs';
mermaid.initialize({ startOnLoad: false });
document.querySelectorAll('code.language-mermaid').forEach(el => {
const pre = el.parentElement;
const div = document.createElement('div');
div.classList.add('mermaid');
div.textContent = el.textContent;
pre.replaceWith(div);
});
await mermaid.run();
</script>
Comment on lines +148 to +159
Copy link
Copy Markdown

@coderabbitai coderabbitai Bot Apr 17, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

⚠️ Potential issue | 🟡 Minor

Mermaid loader runs on every page; consider scoping and adding SRI.

A couple of observations on the new loader:

  • The script is included in the base layout, so every page on the site will fetch ~1MB of Mermaid ESM from cdn.jsdelivr.net even when no diagrams are present. Consider gating execution on the presence of a code.language-mermaid element before importing, e.g. dynamic import() inside an if (document.querySelector('code.language-mermaid')) check, to avoid the network/parse cost on unrelated pages.
  • The CDN script is loaded without a Subresource Integrity (integrity) hash or version pin beyond the major (mermaid@11). A compromised or unexpectedly updated upstream would execute on every page. Pinning to an exact version and adding integrity/crossorigin="anonymous" would harden this.
♻️ Suggested guard to skip the import when no diagrams are on the page 
   <script type="module">
-    import mermaid from 'https://cdn.jsdelivr.net/npm/mermaid@11/dist/mermaid.esm.min.mjs';
-    mermaid.initialize({ startOnLoad: false });
-    document.querySelectorAll('code.language-mermaid').forEach(el => {
+    const blocks = document.querySelectorAll('code.language-mermaid');
+    if (blocks.length === 0) return;
+    const { default: mermaid } = await import('https://cdn.jsdelivr.net/npm/mermaid@11/dist/mermaid.esm.min.mjs');
+    mermaid.initialize({ startOnLoad: false });
+    blocks.forEach(el => {
       const pre = el.parentElement;
       const div = document.createElement('div');
       div.classList.add('mermaid');
       div.textContent = el.textContent;
       pre.replaceWith(div);
     });
     await mermaid.run();
   </script>
📝 Committable suggestion

‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

Suggested change
<script type="module">
import mermaid from 'https://cdn.jsdelivr.net/npm/mermaid@11/dist/mermaid.esm.min.mjs';
mermaid.initialize({ startOnLoad: false });
document.querySelectorAll('code.language-mermaid').forEach(el => {
const pre = el.parentElement;
const div = document.createElement('div');
div.classList.add('mermaid');
div.textContent = el.textContent;
pre.replaceWith(div);
});
await mermaid.run();
</script>
<script type="module">
const blocks = document.querySelectorAll('code.language-mermaid');
if (blocks.length === 0) return;
const { default: mermaid } = await import('https://cdn.jsdelivr.net/npm/mermaid@11/dist/mermaid.esm.min.mjs');
mermaid.initialize({ startOnLoad: false });
blocks.forEach(el => {
const pre = el.parentElement;
const div = document.createElement('div');
div.classList.add('mermaid');
div.textContent = el.textContent;
pre.replaceWith(div);
});
await mermaid.run();
</script>
🤖 Prompt for AI Agents 
Verify each finding against the current code and only fix it if needed.

In `@src/_includes/layout.njk` around lines 148 - 159, The loader unconditionally
imports and runs mermaid causing the CDN fetch on every page and lacks
SRI/crossorigin; change the logic in the script so you first check
document.querySelector('code.language-mermaid') and only then perform a dynamic
import (e.g., import('https://cdn.jsdelivr.net/npm/mermaid@11.X.Y/...') inside
that if) before calling mermaid.initialize(...) and mermaid.run(), and pin the
import URL to an exact mermaid version and add Subresource Integrity and
crossorigin="anonymous" (or load via a script tag with integrity/crossorigin) to
harden the external fetch referenced by mermaid and the code paths that use
document.querySelectorAll('code.language-mermaid'), mermaid.initialize, and
mermaid.run.


<!-- Template Main JS File -->
<script src="/static/js/main.js"></script>

Expand Down
106 changes: 106 additions & 0 deletions src/blog/mcp-gateway-tech-preview/mcp-gateway-tech-preview.md
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,106 @@
---
title: "MCP Gateway 0.6: Tech Preview Release"
date: 2026-04-17
author: David Martin
---

The [MCP Gateway](https://github.com/kuadrant/mcp-gateway) has reached its [0.6 tech preview release](https://github.com/Kuadrant/mcp-gateway/releases/tag/v0.6.0). 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](https://github.com/Kuadrant/mcp-gateway/releases/tag/v0.6.0) on GitHub.

For background on the MCP Gateway, see the previous [0.5 dev preview announcement](/blog/mcp-gateway-dev-preview/) or the [overview documentation](https://docs.kuadrant.io/dev/mcp-gateway/docs/guides/overview/).

## 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:

- **Installation** - OLM operator replaces Helm charts
- **Configuration** - declarative CRD (`MCPGatewayExtension`) replaces manual resource creation
- **Scaling** - Redis session store enables multi-replica deployments
- **Protocol** - elicitation support tracks the evolving MCP specification

## What's New in 0.6

### Kubernetes Operator and MCPGatewayExtension CRD

The 0.6 release adds an [OLM-based installation](https://docs.kuadrant.io/dev/mcp-gateway/docs/guides/olm-install/) 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:

```yaml
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](https://docs.kuadrant.io/dev/mcp-gateway/docs/guides/olm-install/) to get started.

### MCP Specification Elicitation Support

This release adds support for the MCP protocol's [elicitation](https://modelcontextprotocol.io/specification/2025-11-25/client/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.
Copy link
Copy Markdown

@coderabbitai coderabbitai Bot Apr 17, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

⚠️ Potential issue | 🟡 Minor

Minor copy nits.

  • LanguageTool flags a missing comma on line 7: "For the full list of changes**,** you can check out…".
  • Line 48 ends with a trailing space after "from the client."; harmless but worth trimming.
🤖 Prompt for AI Agents 
Verify each finding against the current code and only fix it if needed.

In `@src/blog/mcp-gateway-tech-preview/mcp-gateway-tech-preview.md` at line 48,
Fix two copy nits in the markdown: add a comma after "For the full list of
changes" in the sentence that begins with that phrase, and remove the trailing
space at the end of the sentence that ends with "from the client." (use these
exact sentence fragments to locate the lines in
src/blog/mcp-gateway-tech-preview/mcp-gateway-tech-preview.md).


```mermaid
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](https://modelcontextprotocol.io/) 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:

```yaml
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](https://github.com/Kuadrant/mcp-gateway/milestone/5) includes a review of the virtual server API, tool search and discovery, and an investigation into how [A2A](https://google.github.io/A2A/) fits into the picture, among other items.

## Get Involved

- Try the [getting started guide](https://docs.kuadrant.io/dev/mcp-gateway/docs/guides/getting-started/).
- Report issues or request features on the [MCP Gateway Issues](https://github.com/kuadrant/mcp-gateway/issues) page.
- Engage with the [community](https://kuadrant.io/community/).
Loading