The gate I'd add to your table is the one I ended up building first, and it isn't a stage. It's a column. Every value an agent produces in our system carries who made it and an evidence grade, and the grade is on the value itself, not on the workflow that produced it. Measured, sensed, stated, record, modeled, in that order. An agent writes at the bottom of that ladder no matter how much it searched. What moves a value up is a person, or a tape measure, or a record from the town. That's how I'd handle your logged exception too. The exception is a claim at the stated grade with a name on it, so it never quietly becomes a fact later. I run this on a house record for a construction company in Rhode Island, seven agents and one human, and the honest report is that the ladder caught more than the gates did. Your falsifiable framing at the end is the part I'd steal.