diff --git a/package.json b/package.json
index 0b5faf7..255c10b 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@sequenzy/mcp",
-  "version": "0.0.39",
+  "version": "0.0.41",
   "mcpName": "io.github.sequenzy/mcp",
   "description": "Sequenzy MCP server for AI-powered email marketing automation",
   "type": "module",
diff --git a/server.json b/server.json
index a433615..77eed24 100644
--- a/server.json
+++ b/server.json
@@ -6,12 +6,12 @@
     "url": "https://github.com/Sequenzy/mcp",
     "source": "github"
   },
-  "version": "0.0.39",
+  "version": "0.0.41",
   "packages": [
     {
       "registryType": "npm",
       "identifier": "@sequenzy/mcp",
-      "version": "0.0.39",
+      "version": "0.0.41",
       "runtime": "node",
       "transport": {
         "type": "stdio"
diff --git a/src/tools/index.test.ts b/src/tools/index.test.ts
index 9c11f9d..4663194 100644
--- a/src/tools/index.test.ts
+++ b/src/tools/index.test.ts
@@ -46,6 +46,34 @@ function collectSchemaKeywordPaths(
   return paths;
 }
 
+function collectArraySchemasWithoutItems(
+  value: unknown,
+  path: string
+): string[] {
+  if (Array.isArray(value)) {
+    return value.flatMap((item, index) =>
+      collectArraySchemasWithoutItems(item, `${path}[${index}]`)
+    );
+  }
+
+  if (typeof value !== "object" || value === null) {
+    return [];
+  }
+
+  const record = value as Record<string, unknown>;
+  const paths =
+    record.type === "array" &&
+    !Object.prototype.hasOwnProperty.call(record, "items")
+      ? [path]
+      : [];
+
+  for (const [key, child] of Object.entries(record)) {
+    paths.push(...collectArraySchemasWithoutItems(child, `${path}.${key}`));
+  }
+
+  return paths;
+}
+
 describe("tool schema compatibility", () => {
   it("does not publish unsupported root-level composition keywords", () => {
     const unsupportedRootKeywords = ["anyOf", "oneOf", "allOf", "enum", "not"];
@@ -71,6 +99,14 @@ describe("tool schema compatibility", () => {
 
     expect(violations).toEqual([]);
   });
+
+  it("publishes items for every array schema", () => {
+    const violations = tools.flatMap((tool) =>
+      collectArraySchemasWithoutItems(tool.inputSchema, tool.name)
+    );
+
+    expect(violations).toEqual([]);
+  });
 });
 
 describe("update_template tool validation", () => {
diff --git a/src/tools/index.ts b/src/tools/index.ts
index c9131ba..d6f5c27 100644
--- a/src/tools/index.ts
+++ b/src/tools/index.ts
@@ -2893,6 +2893,7 @@ OTHER BUILT-IN EVENTS:
               blocks: {
                 type: "array",
                 description: "Updated Sequenzy block JSON for the step",
+                items: { type: "object" },
               },
             },
           },
@@ -2939,6 +2940,7 @@ OTHER BUILT-IN EVENTS:
               blocks: {
                 type: "array",
                 description: "Updated Sequenzy block JSON for the step",
+                items: { type: "object" },
               },
             },
           },