The unit of consistency is an attribute
A protocol payload, a vendor account and a resident override may all describe the same physical device differently. A single global source-of-truth rule is insufficient: identity, room binding, tenancy and presentation have different authorities. Studio’s authored model supplies the common context, while downstream App entities, scene and automation surfaces, non-KNX configuration and edge runtime configuration are generated views.
Room ownership is not user identity
FY2026 mixed-vendor reconciliation established Studio’s recorded room as the authority for room binding. Tenancy is resolved from the authored chart, not inferred from the authentication token of the person performing synchronisation. An operator can legitimately configure another project; the acting principal and the device’s owning tenant are therefore different concepts. Treating them as interchangeable can produce a consistent-looking record in the wrong scope.
Entity-level upserts preserve independent overrides
Resident changes must survive repeated publication without overwriting unrelated devices. The recorded implementation moved away from replacing a home’s overrides as one unit and towards per-entity upserts. The important property is mutation granularity: updating one entity should not erase the presentation or assignment state of another. Identity reconciliation and override merging must be evaluated together, because the merge key decides which state is preserved.
A valid project can contain no KNX devices
Pure KNX, cloud-only and mixed compositions exercise different publication paths. An empty KNX configuration is valid for a cloud-only dwelling; treating it as a failure would make the authoring model dependent on one protocol. First publication also needs a valid draft state for a project with no pre-existing chart entry. These are composition invariants, not exceptions to hide in the interface.
Authorship and runtime execution are separate
Generated KNX YAML and Home Assistant configuration carry the authored state towards the edge. Tecco’s contribution described here is the model, reconciliation and surrounding policy. Automation execution on this verified path uses Home Assistant. Keeping that boundary explicit makes integration responsibilities and failure diagnosis clearer.
Validation follows disagreement
The useful test is not whether a publish request returns success. It is whether the installation, authored room, owning tenant and preserved overrides agree afterwards. The FY2026 record describes a capture–correct–retest cycle across mixed-vendor projects. Our architectural direction extends that discipline through versioned design snapshots and installation-specific corrections.