So interrogating Gemini further to clarify the ground truth about the 2016-2019 period gets me to:

The Final Verdict

So, was Iran in compliance? Under the strict text of the JCPOA (2016–2019): Yes. They met the mathematical limits on active enrichment, which is why the UN, the IAEA, and the US State Department repeatedly certified their compliance during that period.

Under the spirit of the deal and international law: No. The premise of the JCPOA was that Iran had to come clean so the IAEA had a baseline to measure against. By hiding the Atomic Archive and keeping secret contaminated sites on standby, Iran proved they negotiated the deal in bad faith and violated their foundational NPT Safeguards.

I can live with that. So if you want to be "technical" sure. Either the agreement was bad and was upheld or it was good and was violated. Either way, Iran has acted in bad faith is the bottom line.

I will add that we don't have evidence that Iran was enriching Uranium in those secret sites during this period (one could even say we have some evidence they weren't). But that still doesn't change that they acted in bad faith and/or the agreement was bad.