Enterprise-Managed Authorization (EMA) is the MCP name for the Identity Assertion Authorization Grant (ID-JAG) that’s been working its way through the IETF for the better part of three years.

What it buys you is simple to describe and strange to experience. You sign into an MCP client with your company SSO, and every MCP server is already connected. No consent screens, no copy-pasted API keys, no credentials configured anywhere.

Arcadians Nate Barbettini and Wils Dawson sat down with Aaron Parecki, Director of Identity Standards at Okta and a longtime OAuth working group participant, and Paul Carleton, a core MCP maintainer at Anthropic on the auth working group, to work through what EMA actually does, who has to implement what, and why the consent prompt was never the employee’s decision to begin with.

In the video, the crew covers:

  • What Enterprise-Managed Authorization is, and how it differs from ID-JAG and Cross-App Access: three names that are mostly, but not exactly, the same thing.
  • Why the OAuth consent prompt is essential in consumer contexts and wrong in enterprise ones: approving “let this app read your email” is a data-sharing agreement made on the company’s behalf.
  • The counterintuitive finding that employees want this more than IT admins do — and that the real admin pressure runs the other way, toward blocking corporate accounts from reaching personal ones.
  • Why the implementation burden is distributed the way it is: accept an ID-JAG on your token endpoint, return the same access token you already return, leave your resource server alone.
  • MCP’s extensions-first approach, why MCP Apps will probably never move into the core spec, and why EMA likely stays an extension too.
  • The iss parameter, mix-up attacks, and how RFC 9700’s two options became MCP’s one option.
  • How MCP dragged dynamic client registration into real adoption after a decade, then moved the recommendation to client ID metadata documents once the auth-failure numbers came in.
  • Predictions for next year: proof-of-possession tokens, the token-theft incident that finally forces the issue, and workload identity for agents.

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