Long time no see! It's been a while since I've looked at MCP, but I think this does a really good job at making MCP more secure for organizations and addressing some of the weaknesses of dynamic client registration. Now that clients and approved redirect URIs can be setup directly by the IdP and organization, a lot of the attacks that were possible with DCR (confused deputy, phishing attacks, etc.) can be mitigated more broadly. It also makes it so servers don't have to implement as much authorization logic as they did before if the IdP or organization didn't support DCR, which is a pretty big advantage (especially if they combine MCP auth with existing API auth).

One major downside is consumer usage seems to still need DCR with this. I think this could potentially be addressed by existing consumer OAuth providers (Sign in with GitHub, GitLab, Google, etc.) adding support for registering static MCP clients/servers, clients shipping their static client IDs inside them, clients allowing users to sign in with GitHub/GitLab/whatever IdP, and letting the user self-manage connections on the IdP's site.

Overall, XAA/EMA seems vastly superior to DCR from a security perspective (and also usability too, since users don't have to configure as much!). The concerns I have are also much easier to address and have way less security impact than with DCR, since attackers don't get to register their own clients anymore and there are less pitfalls for MCP server developers.

This is great for normal "apps". We have a really deep need for a lower touch way for our users to interact with us agentically without setting up MCP. It'd be really great to have some sort of temporary session or out-of-band token storage available.

Here's our use case: During the sales cycle, the buyer and seller need to exchange a bunch of information then analyze it (which is increasingly agentic). The problem with MCP is the initial setup friction is far greater than users login in themselves and grabbing the information they need. MCPs are great for regular, frequent interactions - but create a lot of problems for these quick one-off sessions.

We'd really love a way to do something like this:

* In Claude: "Grab documents from X, Y, Z"

* Claude hits that website, it returns (1) basic usage information (2) a login link that the user can open in their browser

* User auths in their browser (annoying, but mindless)

* That callback returns a unique, short-lived, one-time token that gets exchanged on all future requests to the site.

Now, we can quickly auth users AND maintain a session state as they do things.

Fantastic news. Is there any communication between you folks and the Microsoft Entra (Azure AD) team? Would love to know if we can expect this soon or if will take a while.

Hiya, congrats on shipping!

Seems like the main use case is employees of companies. Is there an analogous use case/value for non-centralized users like customers or freemium users?

I'm struggling to think of one, but wonder what I'm missing.

Edit: I see you addressed this here: https://news.ycombinator.com/item?id=48594381

Great work, thank you for doing this. Just so I understand, this isn't yet available yet, right? Still in SEP stage?

Anthropic is the only one with human readable tool names from the JUNE 2025 spec! So you guys are doing a great job and this is another example.

I'm just curious internally how you are seeing MCP adoption? It seems more and more connectors are created but are you seeing real adoption from users?