diff --git a/packages/mcp-core/src/api-client/client.test.ts b/packages/mcp-core/src/api-client/client.test.ts
index 4924514aa..4b73c4710 100644
--- a/packages/mcp-core/src/api-client/client.test.ts
+++ b/packages/mcp-core/src/api-client/client.test.ts
@@ -1800,6 +1800,44 @@ describe("API query builders", () => {
       expect(params.get("attributeType")).toBeNull();
     });
 
+    it("should accept 'array' as a valid attributeType", async () => {
+      const apiService = new SentryApiService({
+        host: "sentry.io",
+        accessToken: "test-token",
+      });
+
+      globalThis.fetch = vi.fn().mockResolvedValue({
+        ok: true,
+        headers: {
+          get: (key: string) =>
+            key === "content-type" ? "application/json" : null,
+        },
+        json: () =>
+          Promise.resolve([
+            {
+              key: "tags[items]",
+              name: "items",
+              attributeType: "array",
+              attributeSource: { source_type: "user" },
+            },
+          ]),
+      });
+
+      const result = await apiService.listTraceItemAttributes({
+        organizationSlug: "test-org",
+        itemType: "spans",
+      });
+
+      expect(result).toEqual([
+        {
+          key: "tags[items]",
+          name: "items",
+          type: "array",
+          attributeSource: { source_type: "user" },
+        },
+      ]);
+    });
+
     it("should validate events requests via the validate endpoint", async () => {
       const apiService = new SentryApiService({
         host: "sentry.io",
diff --git a/packages/mcp-core/src/api-client/client.ts b/packages/mcp-core/src/api-client/client.ts
index 6530a396f..6dda39f1e 100644
--- a/packages/mcp-core/src/api-client/client.ts
+++ b/packages/mcp-core/src/api-client/client.ts
@@ -325,7 +325,7 @@ type UpdateClientKeyRequest = {
   browserSdkVersion?: string;
   dynamicSdkLoaderOptions?: ClientKeyDynamicSdkLoaderOptions;
 };
-export type TraceItemAttributeType = "string" | "number" | "boolean";
+export type TraceItemAttributeType = "string" | "number" | "boolean" | "array";
 export type TraceItemAttributeSourceType = "sentry" | "user";
 
 export type TraceItemAttributeSource = {
@@ -381,7 +381,7 @@ export type EventsValidationResult = {
   orderby: EventsAttributeValidationResult[];
 };
 
-const TraceItemAttributeTypeSchema = z.enum(["string", "number", "boolean"]);
+const TraceItemAttributeTypeSchema = z.enum(["string", "number", "boolean", "array"]);
 const TraceItemAttributeSourceSchema = z.object({
   source_type: z.enum(["sentry", "user"]),
   is_transformed_alias: z.boolean().optional(),
diff --git a/packages/mcp-core/src/tools/support/search-events/utils.ts b/packages/mcp-core/src/tools/support/search-events/utils.ts
index 79028959a..431f3c952 100644
--- a/packages/mcp-core/src/tools/support/search-events/utils.ts
+++ b/packages/mcp-core/src/tools/support/search-events/utils.ts
@@ -950,7 +950,7 @@ export function createDatasetAttributesTool(options: {
   projectId?: string;
 }) {
   const { apiService, organizationSlug, projectId } = options;
-  const traceItemAttributeTypeSchema = z.enum(["string", "number", "boolean"]);
+  const traceItemAttributeTypeSchema = z.enum(["string", "number", "boolean", "array"]);
 
   return agentTool({
     description: