Hi Laxmikant,
Just a quick follow-up to let you know that we have seen the proposed text you 
submitted on GitHub (Issue #30). 
Thank you for putting this together and opening the issue so quickly! We will 
review the text and incorporate it into the draft as soon as possible. 
We will keep you and the working group updated once the new version is ready.
Best regards,
Meiling


[email protected]
 
From: Laxmikant Sharma
Date: 2026-09-25 12:58
To: oauth
CC: draft-chen-oauth-agent-authz-use-cases
Subject: draft-chen-oauth-agent-authz-use-cases: data on responding to resource 
server challenges
Hi all,

Ahead of the 19 October interim on agent authorization use cases
and gaps, here is some data on one of the gaps in
draft-chen-oauth-agent-authz-use-cases. Section 6 (item 2) notes
that the framework has no built-in mechanism for an agent "to
respond to a real-time authorization challenge from a resource
server".

In September I ran eight shipped AI agents that act as MCP
clients, in their mid-September releases, against a resource
server that answered the first request with 401 and a
WWW-Authenticate header carrying resource_metadata. The
authorization server offered the authorization code grant with
PKCE and accepted both client ID metadata documents and dynamic
registration. Each client ran in a terminal on a machine with a
browser, and a scripted test user completed any sign-in page a
client opened or printed.

In one-shot mode, one client completed the grant on its own, and a
second did so only after the user set a per-server flag in its
configuration. Two fetched the protected resource metadata, one of
them also registered a client, and both stopped there. The other
four made no authorization attempt, although one of them opened
the browser within seconds and completed the grant when run as an
interactive session instead. In a separate run the day before, all
eight completed the same grant through their own sign-in steps.

So every client can run the grant, and whether it runs it on a
challenge is left to the client. A client that won't act on the
challenge also has no standard way to say so, which leaves the
resource server nothing to fall back on.

Use Case 5 (Section 4.1.6) covers first connection when there is
no front channel. This is the complementary case, where the front
channel exists and the client doesn't use it. If the authors think
it belongs in the document, I'm glad to open an issue on their
tracker with proposed text. I also plan to publish the harness and
the records once each client's maintainers have seen their results.

Thanks,
Laxmikant Sharma
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