Why DataHub

A check learns something the next run would otherwise rediscover. A private cache helps only MCMR. DataHub lets engineers, dashboards, and later agents read the same conclusion beside the asset it describes.

[tool.mcmr.execution]
external = true

[tool.mcmr.providers.datahub]
server = "http://localhost:8080"
publish_runs = true

Set DATAHUB_GMS_TOKEN when the server requires authentication. Secrets never belong in project configuration.

Reading and writing stay separate

External rules can read DataHub without publishing anything. Writeback happens only through --writeback or publish_runs = true. --no-writeback suppresses a configured default for one run.

mcmr check . --external --writeback

Ordinary source findings attach to the fact dataset queried by the rule. A rule that names a governed asset directly stores its verdict on that asset instead.

Ownership and attribution

Projects can name a human owner and an agent operator. Contextual verdicts also record the actual backend and model. MCMR invents no identity when none is configured.

An owner, domain, and report URL can make results discoverable from the first run. An unset report URL stays absent instead of producing a dead link.

What crosses the integration boundary is structured run data. It includes verdicts, measurements, repairs, facts, lineage, and model usage. The provider does not reanalyze the source.

See What gets published for the entity map.