Expression Compatibility
Which expressions can work together
Expression compatibility declarations define which expression kinds can safely coexist in a single deployment, federate across deployments, and exchange coordination records without governance ambiguity.
Declared, not inferred
Expression compatibility is declared in the expression manifest, not inferred from technical capability. Two expressions that are technically compatible may still be declared incompatible if their governance models conflict.
Composition rules
When expressions are admitted together in a hybrid deployment, composition rules define which governance primitive takes precedence in cases of conflict. Composition is always explicit, the substrate does not resolve governance conflicts silently.
Cross-expression federation
Deployments running different expressions can federate if both expressions declare cross-expression federation compatibility. The federation event protocol handles the translation between coordination vocabularies, so participants on different expressions can exchange attested events.