Thing Model v1 alpha 1

Authoritative source: AetherContracts. This page is mirrored into the unified AetherIoT documentation.

A Thing Model is an immutable, industry-neutral definition. It describes configuration properties, edge-observed points, and governed capabilities. It does not contain tenant instances, live values, credentials, register bindings, or customer topology.

Every published revision has one model_id, canonical positive revision, and canonical artifact digest. The digest belongs to the external publication record because a self-hashed Thing Model cannot contain its own digest; it is therefore deliberately absent from thing-model.schema.json. Reusing a revision for different canonical bytes is forbidden. Keys must be unique across the property, point, and capability namespaces; this is a semantic validation rule in addition to JSON Schema. Parameter keys must also be unique within each capability so request payloads cannot have ambiguous meanings.

The publication digest is sha256: plus lowercase SHA-256 of RFC 8785 JCS over the complete Thing Model object accepted by thing-model.schema.json. No publication wrapper or tenant metadata enters that projection. The machine-readable rule is profiles/thing-model/v1alpha1/publication.json.

Authority

Properties are owned by an immutable artifact revision. Changes are applied by an artifact deployment or by an explicitly edge-local path, never by a direct field write.
Points are edge-authoritative, read-only observations. Cloud history and projections are not live-state authority.
Capabilities declare what an edge may understand. Every capability is deny-by-default, requires a permission, risk class, confirmation policy, idempotency, expiry, and audit policy, and executes only as a governed job. The edge makes the final accept, reject, expire, or apply decision.

Desired, Reported, and Applied are distinct facts. Desired is Cloud intent; Reported is an edge observation of support; Applied is edge-reported deployment evidence. None may be inferred from another solely because a message was sent or a transport acknowledgement arrived.

An applied observation carries a non-null model reference and applied_at_ms. not-applied carries a null model and no applied timestamp; applying and failed identify the attempted model but do not fabricate an apply time. The root observed_at_ms timestamps every observation state.

Voltage migration profile

The structural migration is:

P becomes properties.
M becomes points.
A becomes capabilities.
pName becomes taxonomy or composition metadata outside the core model.
legacy numeric IDs are retained as namespaced aliases, never as global IDs.

Unit spellings are normalized while the legacy spelling is retained as provenance. Ambiguous source types, arrays represented as scalars, duplicate meaning, and uncertain units require an explicit migration diagnostic; an importer must not guess silently.

The minimal fixture is structurally informed by EvanL1/voltage-product-lib at commit 7c4eec680f8b5e9a76a57c08078a41b9d5b4550c. The source repository had only a README statement claiming MIT and no standalone LICENSE at import time, so the catalog was not copied. The fixture is not a normative energy model pack.

WoT relationship

The vocabulary is aligned with W3C Web of Things properties, events, actions, and reusable Thing Models for future import/export. JSON-LD processing is not a v1 alpha core requirement. A WoT action maps only to an Aether capability declaration and never grants direct physical execution.