Message families

A family is a payload schema. The envelope's message_type selects it, and nothing else does: not the topic, not the producer, not the payload's shape.

Family (schema)	message_type	What it says	Typical producer
story-context	story.context	The complete state of a story at one moment: headline, story_type, sources, assets, gates, compliance. See Snapshots, not deltas	NCS or planning system
telling-event	telling.started, telling.ended, telling.exposed	A story going out on a platform	Playout, CMS, social publishing
link-event	link.committed, link.gate_changed, link.withdrawn	An asset committed to, or withdrawn from, a destination	Graphics, CMS, rundown
delivery-media-available	delivery.media_available	Media has arrived in a store. The message carries a reference, never the media	MAM, media store, ingest
skill-warning	skill.warning.raised	An AI skill flags something for editorial attention	Skill executor
system-audit	system.audit	Governance trail: clearances, suppressions	Compliance and standards desk tools

Every field of every family, what it means and where that meaning comes from, is in the SOM 1.0 schema reference.

GET /v1/health lists the message types the bus has a schema for (see the Bus API).

The published examples for every family are in the SOM repository, along with negative examples that must be refused. The bus accepts every positive example and refuses every negative one.

Message types without a schema

SOM 1.0 names some message types without publishing a schema for them, and a later 1.x may add families. The bus accepts these with the envelope checked and the payload passed through, and says so: payload.unvalidated. Many skill recall_on topics are in this group.

Consumers must ignore message types they don't recognise.