Generalize live field bindings and use them for Studio canvas gestures

src/capability-model/generics.ts

@@ -98,6 +98,7 @@ export const instantiateInterface = (
         return {
           ...common,
           kind: "value",
+          ...(member.nativeField ? { nativeField: true as const } : {}),
           ...(member.queryRead ? { queryRead: { ...member.queryRead } } : {}),
           valueType: substitution.value(member.valueType, member.displayName),
         };

src/capability-model/types.ts

@@ -132,6 +132,8 @@ interface InterfaceMemberBase<Type = ValueType> {
 
 export interface ValueInterfaceMember<Type = ValueType> extends InterfaceMemberBase<Type> {
   kind: "value";
+  /** Every operation resolves directly to the same native state slot. */
+  nativeField?: true;
   queryRead?: QueryReadContract;
   valueType: Type;
 }

src/capability-model/validation.ts

@@ -615,6 +615,23 @@ const collectIdentityIndexes = (
             );
         }
       }
+      if (member.kind === "value" && member.nativeField) {
+        const names = member.operations.map((o) => o.displayName);
+        if (
+          !isStorableType(member.valueType) ||
+          !names.includes("get") ||
+          names.some((n) => !["get", "set", "edit"].includes(n)) ||
+          (names.includes("set") && names.includes("edit"))
+        )
+          issue(
+            issues,
+            "invalid-state-binding",
+            memberPath,
+            "Fields require a storable value, a native getter and at most one setter or editor",
+          );
+        if (member.queryRead && member.queryRead.execution !== "native")
+          issue(issues, "invalid-query-contract", memberPath, "Fields cannot have package-backed query reads");
+      }
       requireText(issues, member.id, `${memberPath}.id`, "Member ID");
       requireText(issues, member.displayName, `${memberPath}.displayName`, "Member name");
       if (memberIds.has(member.id)) {
@@ -1758,6 +1775,34 @@ const validateConformances = (
         }
       } else binding = entry.binding;
       const member = operationEntry.member;
+      if (member.kind === "value" && member.nativeField) {
+        const primitive = { get: "read", set: "write", edit: "edit" }[operation.displayName];
+        const getter = member.operations.find((o) => o.displayName === "get");
+        let read: Binding | undefined;
+        try {
+          if (getter)
+            read = resolveForwardedBinding(
+              workspace,
+              conformance.atomId,
+              conformance.interfaceRevisionId,
+              getter.id,
+            ).binding;
+        } catch {}
+        if (
+          binding.kind !== "state" ||
+          binding.primitive !== primitive ||
+          read?.kind !== "state" ||
+          read.primitive !== "read" ||
+          read.slotId !== binding.slotId
+        )
+          issue(
+            issues,
+            "invalid-state-binding",
+            bindingPath,
+            "Field operations must resolve to the same native state slot",
+          );
+      }
+
       if (
         member.kind === "value" &&
         operation.displayName === "edit" &&