The medallion architecture is a slide

Ask three teams what belongs in silver and you will get four answers, two of them from the same team. This is the tell. Real architectures survive cross-examination; vocabularies do not.

The medallion pattern, as canonised by Databricks, says data lands raw in bronze, gets cleaned into silver, and is served curated from gold. As a napkin sketch this is fine. It is also the layered-staging idea that warehouse teams shipped under duller names for twenty years: landing, staging, marts. The rebrand added colours and removed definitions.

What the label does not tell you: whether silver is deduplicated, whether gold is dimensional, whether schema enforcement happens at the border or inside, who owns the contract between layers, or what a consumer may safely read. Every one of those is the actual architecture. Every one is left as an exercise for the team, which is how a "medallion" estate ends up with five bronzes and a folder named gold_final_v2.

We keep meeting the same failure. A platform proposal clears review because the slide shows three tidy arcs, and eighteen months later the estate has forty models in silver whose only shared property is that nobody will vouch for them. The colour told the reviewer nothing; it just ended the conversation early. We said something similar about semantic layers: naming a wish is not building the thing.

Our advice is unglamorous. Keep the layers if they help, but write down, per layer, the contract: allowed sources, enforced schema, dedup guarantee, ownership, retention. One page does it. If the page is hard to write, you did not have an architecture, you had a slide.

Verdict on the vocabulary: marketing, successful, mostly harmless. Verdict on shipping it as your design: no.