A function-invocation filter skips next when the bearer is missing or userinfo rejects it. The function runs only on the path that calls next.
Getting started, including the planned sample, is Semantic Kernel.
What fails closed
Invoking whoami with no token does not enter the function. The result is not a subject.
Invoking whoami with a bearer userinfo accepts runs the function. The result is that subject.
A resolved subject is not authorization. Scopes and allowed tools are a later check. The trust-store sample is that later check for MCP. This page stops at admission.
Related
| Read | To learn how to |
|---|---|
| Semantic Kernel | See the hook |
| API keys and M2M for Semantic Kernel | Where the secret is allowed to live |
| Authorizing tool calls for Semantic Kernel | What happens after the subject is known |