diff --git a/packages/project/src/package.ts b/packages/project/src/package.ts
index 5b5f376..252a8d6 100644
--- a/packages/project/src/package.ts
+++ b/packages/project/src/package.ts
@@ -23,14 +23,16 @@ const DependenciesSchema = z.record(NameSchema, VersionFormat);
 const RegistryUrisSchema = z.array(z.string());
 export const JaculusProjectTypeSchema = z.enum(["code", "jacly"]);
 
-const JaculusSchema = z.object({
-    registry: RegistryUrisSchema.optional(),
-    blocks: z.string().optional(),
-    projectType: JaculusProjectTypeSchema.optional(),
-    template: z.boolean().optional(),
-    projectFormatVersion: z.number().optional(),
-    jaclyVersion: VersionFormat.optional(),
-});
+const JaculusSchema = z
+    .object({
+        registry: RegistryUrisSchema.optional(),
+        blocks: z.string().optional(),
+        projectType: JaculusProjectTypeSchema.optional(),
+        template: z.boolean().optional(),
+        projectFormatVersion: z.number().optional(),
+        jaclyVersion: VersionFormat.optional(),
+    })
+    .catchall(z.unknown());
 
 const ExportKeyValueSchema = z.record(z.string(), z.string());
 
diff --git a/test/project/package.test.ts b/test/project/package.test.ts
index aae2bd4..20ce65c 100644
--- a/test/project/package.test.ts
+++ b/test/project/package.test.ts
@@ -32,7 +32,9 @@ describe("Package JSON", () => {
                     core: "0.0.24",
                     "led-strip": "1.2.3",
                 },
-                registry: ["https://registry.example.com", "https://backup.registry.com"],
+                jaculus: {
+                    registry: ["https://registry.example.com", "https://backup.registry.com"],
+                },
             };
 
             const packagePath = path.join(tempDir, "package.json");
@@ -46,7 +48,9 @@ describe("Package JSON", () => {
             expect(loaded.description).to.equal("A test package");
             expect(loaded.dependencies).to.have.property("core", "0.0.24");
             expect(loaded.dependencies).to.have.property("led-strip", "1.2.3");
-            expect(loaded.registry).to.be.an("array").that.includes("https://registry.example.com");
+            expect(loaded.jaculus?.registry)
+                .to.be.an("array")
+                .that.includes("https://registry.example.com");
         });
 
         it("should load minimal valid package.json with only dependencies", async () => {
@@ -68,7 +72,7 @@ describe("Package JSON", () => {
             expect(loaded.name).to.equal("minimal-package");
             expect(loaded.version).to.equal("1.0.0");
             expect(loaded.description).to.be.undefined;
-            expect(loaded.registry).to.be.undefined;
+            expect(loaded.jaculus).to.be.undefined;
         });
 
         it("should load package.json with empty dependencies", async () => {
@@ -263,7 +267,9 @@ describe("Package JSON", () => {
                     core: "0.0.24",
                     "led-strip": "1.2.3",
                 },
-                registry: ["https://registry.example.com"],
+                jaculus: {
+                    registry: ["https://registry.example.com"],
+                },
             };
 
             await savePackageJson(mockFs, path.join(tempDir, "package.json"), packageData);
@@ -384,7 +390,9 @@ describe("Package JSON", () => {
                     core: "0.0.24",
                     "test-lib": "2.1.0-beta",
                 },
-                registry: ["https://test.registry.com", "https://backup.registry.com"],
+                jaculus: {
+                    registry: ["https://test.registry.com", "https://backup.registry.com"],
+                },
             };
 
             await savePackageJson(mockFs, path.join(tempDir, "roundtrip.json"), originalData);
diff --git a/test/project/testHelpers.ts b/test/project/testHelpers.ts
index 4c25802..cd1ad6d 100644
--- a/test/project/testHelpers.ts
+++ b/test/project/testHelpers.ts
@@ -155,8 +155,11 @@ export function createPackageJson(
         name: "test-project",
         version: "0.0.1",
         dependencies,
-        registry,
         ...additionalFields,
+        jaculus: {
+            registry,
+            ...(additionalFields.jaculus || {}),
+        },
     };
 
     fs.mkdirSync(projectPath, { recursive: true });
@@ -176,7 +179,7 @@ export async function createMockRegistry(
     logger: Logger = createMockLogger()
 ): Promise<Registry> {
     const pkg = await loadPackageJson(fs, path.join(projectPath, "package.json"));
-    return new Registry(pkg.registry, getRequest, logger);
+    return new Registry(pkg.jaculus?.registry, getRequest, logger);
 }
 
 export function createTestDir(prefix: string = "jaculus-test-"): string {
@@ -200,7 +203,7 @@ export function createProjectStructure(
         createPackageJson(
             projectPath,
             packageData.dependencies || {},
-            packageData.registry || [registryBasePath],
+            packageData.jaculus?.registry || [registryBasePath],
             packageData
         );
     } else {