What is the expectation around the tenant parameter

[emmanuelbernard]

Hi,

I am reviewing the 1.0 spec and was digging on the tenancy concept. The spec says very little about it.
I am having difficulties to understand how and why is would be used.
Tenant is a free string passed by the client, so the server must do some validation here. And I suppose it has to be done through the AuthN/Z aspect, not the tenant id aspect (for validation and also because AgentCards are not tenant aware).

I think my main questions are

1. What flow were the spec writers expecting for tenant id?
2. What use cases were the spec writers expecting for tenant id (customer isolation, org isolation, technical sharding, something else?)
3. how is a client expected to discover the tenant id it should use?

Many thanks for any light you should shine on this topic.

Emmanuel