diff --git a/packages/database/src/crossAppContracts.ts b/packages/database/src/crossAppContracts.ts
index c996332c3..94f97f9d7 100644
--- a/packages/database/src/crossAppContracts.ts
+++ b/packages/database/src/crossAppContracts.ts
@@ -1,5 +1,5 @@
 import type { ContentType } from "@repo/content-model";
-import { Enums } from "./dbTypes";
+import { Enums, type Json } from "./dbTypes";
 
 export type LocalRef = {
   // This localId is expected to be unique within the current space
@@ -21,18 +21,67 @@ export type CrossAppBase = LocalRef & {
   author: Ref;
 };
 
+export type CrossAppSchemaBase = CrossAppBase & {
+  metadata?: Json;
+};
+
+type SpaceRef = DbRef | { url: string; sourceApp: Enums<"Platform"> };
+
+export type LocalOrRemoteRef =
+  | LocalRef
+  | {
+      localId: string;
+      // infer space from context if absent.
+      space?: SpaceRef;
+    }
+  | {
+      // A string that contains combined space and localId
+      rid: string;
+    };
+
+// A node schema
+export type CrossAppNodeSchema = CrossAppSchemaBase & {
+  label: string;
+  template?: string;
+  templateTitle?: string;
+};
+
+// A relation type schema
+export type CrossAppRelationTypeSchema = CrossAppSchemaBase & {
+  label: string;
+  complement: string;
+  // should we add colour? format?
+};
+
+// A relation triple schema
+export type CrossAppRelationTripleSchema = CrossAppSchemaBase & {
+  label: string;
+  complement: string;
+  relation?: Ref | CrossAppRelationTypeSchema;
+  sourceType: Ref;
+  destinationType: Ref;
+};
+
 // An inline vector semantic embedding
 export type CrossAppEmbedding = {
   value: number[];
   embedding?: Enums<"EmbeddingName">;
 };
 
+// An inline document, to put inside Content (or Concept)
+export type InlineCrossAppDocument = Partial<CrossAppBase> & {
+  // MIME type
+  contentType: string;
+};
+
 // A Content object. It can be put inline inside a concept.
 // Missing CrossAppBase attributes are inferred from enclosing object.
 export type InlineCrossAppContent = Partial<CrossAppBase> & {
   value: string;
   embedding?: CrossAppEmbedding;
   scale?: Enums<"Scale">;
+  partOf?: Ref;
+  document?: InlineCrossAppDocument;
   contentType?: ContentType;
 };
 
@@ -48,4 +97,13 @@ export type CrossAppNode = CrossAppBase & {
     direct: InlineCrossAppContent;
     full: InlineCrossAppTypedContent;
   };
+  // This is a way to define document globally for all contents
+  document?: InlineCrossAppDocument;
+};
+
+// A relation instance
+export type CrossAppRelation = CrossAppBase & {
+  relationType: Ref;
+  source: LocalOrRemoteRef;
+  destination: LocalOrRemoteRef;
 };