engineering: Datadog MCP URL uses the /unstable endpoint, which Datadog shuts off on December 15, 2026 #1279

What's wrong

engineering/.mcp.json points the Datadog MCP server at Datadog's old endpoint:

"datadog": {
  "type": "http",
  "url": "https://mcp.datadoghq.com/api/unstable/mcp-server/mcp"
}

Datadog is shutting off the /api/unstable/mcp-server/* endpoint on December 15, 2026. They emailed org admins about it on October 5, 2026. After that date, any client still pointed at /unstable gets an error on connect, so everyone using the engineering plugin loses the Datadog tools.

Datadog also says the stable /v1 endpoint fixes authentication errors some users hit on /unstable, so this change may help before the cutoff too.

This URL came in with #238 in May, when /unstable was the documented endpoint.

Fix

Swap in the stable /v1 endpoint for the US1 site (the plugin already hardcodes US1):

     "datadog": {
       "type": "http",
-      "url": "https://mcp.datadoghq.com/api/unstable/mcp-server/mcp"
+      "url": "https://mcp.datadoghq.com/v1/mcp"
     },

Datadog says it's only a URL change. Credentials, scopes, and tool names stay the same.

Sources

• Datadog MCP Server setup docs: https://docs.datadoghq.com/mcp_server/setup. The page fills in the endpoint from a site picker, so the URL doesn't show in the raw page.
• The per-site values in the Datadog docs source (mcp_server_endpoint, US1 is https://mcp.datadoghq.com/v1/mcp): https://github.com/DataDog/documentation/blob/6af7c04eb3203817f9000797e501dfc8fc133427/hugo/assets/scripts/config/regions.config.js#L837-L847

What I checked

On October 5, 2026, an MCP initialize POST with no credentials returns 401 (live, wants auth) for both the old URL and https://mcp.datadoghq.com/v1/mcp. A guess at https://mcp.datadoghq.com/api/v1/mcp-server/mcp returns 404, so the new path is /v1/mcp, not the old path with v1 swapped in.

I'd have sent a PR, but close-external-prs.yml closes PRs from outside contributors, so I'm filing this instead. It's a one-line change.