Signal provenance
Every number carries where it came from — measured, estimated, or unavailable.
Every number Prism shows carries a record of where it came from. That is why Prism sometimes shows you nothing.
The problem
A dashboard that says "Test coverage: 62%" without saying whether that was measured, estimated, stale, or a default is decoration — or worse, confident fiction.
What Prism does
| Provenance | Meaning |
|---|---|
| Measured | Prism ran something, or read a real artefact |
| Derived | Computed from the index by a deterministic rule |
| Estimated | Inferred from indirect evidence — directionally useful |
| Unavailable | Prism does not know, and will not pretend to |
Surfaces show this: markers in the extension, fields in --json, labels in the
CLI. Estimated figures are labelled; unavailable ones are absent rather than
zero.
Unavailable is a real answer
No git history → no ownership section (not "0 contributors"). No coverage
report → no coverage figure (not 0%). A zero and an absence mean different
things.
Estimated is honest, not useless
Health history on day one may backfill earlier points from git, marked estimated. As real snapshots accumulate, they replace estimates. Both appear, distinguished.