Hi,
I was testing my auth0 configuration with MCP Inspector and ran into a discussion on github.
The keyword audience
was only used to the description of the concept. It is not a registered parameter. The registered parameter is resource
. I guess most MCP client only supports the resource
parameter.
This makes integrating with popular cloud LLM provider difficult. How will auth0 address issue?
Thanks
Hi @davidshen84
.
You’re right, Auth0 has supported the audience
parameter as the way to signal the aud
claim in access tokens since ~2017 (long before RFC 8707’s resource
parameter was adopted). However, the audience
parameter is included in the IANA registry for OAuth Parameters, so its presence is acknowledged by the registry (though it’s primarily called out in specs like Token Exchange).
For now though, it appears like much of the MCP tooling has converged on resource
parameter. In the short-term, you’ll need to try to override that parameter when possible.
Longer-term, we’re advocating for broader inclusion of the audience
parameter in tooling, and have future plans to allow Auth0 tenants to use the resource
parameter instead of audience
.
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Hi Josh,
Thanks for the reply.
As for “try to override”, do you have any recommendations?
If we implement our own chatbot, we are in control of the MCP Client. Changing the parameter name is easy. But if we are integrating our MCP server into other’s chatbot, such as Claude web or Claude desktop, they are in control of the MCP client. How can one override the parameter in this case?
Thanks.
2 Likes
Hey @josh.cain! 
Just dropping in to voice my support for including resource
for the same reason as above. I was trying to think through how to work around this but, because aud
is a core claim and the consent needs to happen before the token is minted, this would need to be on on the initial authorize URL and not in Actions. Client side with a UL template does not appear to be possible (and is kind of hacky too).
Any other creative ideas here? Thank you!