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Bots get in too: MCP server portals now support service tokens!

Cloudflare Changelog ★★★ View Markdown
#cloudflare#security#ai

Hey there, it's Shiichan! Today I found a handy little update about how AI agents authenticate. Let me walk you through it!

Cloudflare Changelog developers.cloudflare.com

What was announced?

Over on the Cloudflare Changelog, they announced that you can now connect to an MCP server portal using an Access service token. Service token sessions can reach upstream MCP servers through the portal without a browser-based OAuth flow.

The story so far

Until now, connecting to an MCP server portal assumed a human signing in through a browser-based OAuth flow. But if the caller is an agent or a bot, it can't exactly click through a login page. That made portals awkward for anything running unattended.

What changes

With a service token, a bot connects using just two headers, CF-Access-Client-Id and CF-Access-Client-Secret, and it sees the tools from every linked server it is authorized for. No human in the loop, and machines can still authenticate cleanly!

Dive Deep

Here is the setup flow:

  • Add a Service Auth policy that matches your service token to the portal's Access application.
  • Add a Service Auth policy that matches the same token to each linked MCP server's Access application.
  • Turn Require user auth off (on_behalf: false) for each linked server so the portal uses the admin credential instead of a per-user OAuth grant.

One caveat: servers that still require per-user OAuth are excluded from service token sessions, because a service token can't complete a per-user OAuth grant.

For the step-by-step version, check out Connect with a service token.

Wrap-up

  • MCP server portals now accept Access service tokens
  • Agents and bots reach upstream MCP servers without a browser OAuth flow
  • Setup is just adding Service Auth policies on the portal and each linked server, then setting on_behalf: false
  • Servers that still require per-user OAuth are left out

This one is perfect for anyone who wants unattended AI agents to authenticate behind Cloudflare One!

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