Where does validation stop: at the STAC JSON, or inside the data files?

[nlebovits]

Some of our rules can be checked by reading STAC JSON alone (links resolve, required fields exist, bboxes are valid). Others can only be checked by opening the actual data files — is this GeoTIFF really tiled as a COG? does this Parquet file really have GeoParquet metadata? The question: does spec conformance include the data-level checks, or does it stop at the metadata?

This matters practically because we plan to extract validation into a standalone package (reis). A pure-metadata validator is a small library with light dependencies that anyone can run anywhere. A validator that opens data files needs raster and Parquet readers and becomes a much heavier thing. Both are legitimate — we just have to draw the line on purpose.

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Part of the July 2026 spec sprint. Hub: discussion #570 · work tracker: epic #564 · everything here carries the spec-sprint label.

[m-mohr]

Tendency towards at least validating the embedded file metadata. If something is wrong in a deployment, we should be able to point people how to check their catalogs, otherwise it gets too complicated.