So, this is a tough enough problem for me to resolve that I wanted to talk it out here first.
Currently, in the Development environment, everything is working fine. But in production, logging in doesn’t redirect me to inside the app. I get a success toast, but I remain on the login page. Navigating directly to an interior page just brings me back to login. Some other deep links result in 404s.
How do I ask the Agent for help if the agent can’t observe this behavior?
Common problem. User auth is terrible with Agent/Assistant.
have you checked deployment logs?
Didn’t even know those were a thing! Looking now.
yea if you notice something wrong you can just tell the assistant - these are the logs from prod, fix it asap! 
And…no errors.
But - I just asked the Agent what to do, described the problem, and it recommended a solution that worked! (Setting a session secret.) I was skeptical because it wasn’t clear what had caused the regression, but I was pleasantly surprised. It seemed to have fixed what appeared to be routing issues as well.
Nice work! Congrats on fixing the problem!
After seeing you got the 404 error, my first reaction was routing issue. During development, the routing is to local IP and port. Once you deploy it, the routing now becomes your domain. That breaks the local routing.
Hope this helps!
I was having plenty of routing problems earlier today so that was my assumption, too. But they were always shared across PROD and DEV.