diff --git a/src/cloudflare/internal/ai-api.ts b/src/cloudflare/internal/ai-api.ts
index 5e6b51f9c65..e189f830ac8 100644
--- a/src/cloudflare/internal/ai-api.ts
+++ b/src/cloudflare/internal/ai-api.ts
@@ -42,7 +42,7 @@ export type AiOptions = {
 };
 
 export type AiInputReadableStream = {
-  body: ReadableStream;
+  body: ReadableStream | FormData;
   contentType: string;
 };
 
@@ -87,14 +87,12 @@ export class AiInternalError extends Error {
   }
 }
 
-// TODO: merge this function with the one with images-api.ts
 function isReadableStream(obj: unknown): obj is ReadableStream {
-  return !!(
-    obj &&
-    typeof obj === 'object' &&
-    'getReader' in obj &&
-    typeof obj.getReader === 'function'
-  );
+  return obj instanceof ReadableStream;
+}
+
+function isFormData(obj: unknown): obj is FormData {
+  return obj instanceof FormData;
 }
 
 /**
@@ -111,9 +109,9 @@ function findReadableStreamKeys(
       value &&
       typeof value === 'object' &&
       'body' in value &&
-      isReadableStream(value.body);
+      (isReadableStream(value.body) || isFormData(value.body));
 
-    if (hasReadableStreamBody || isReadableStream(value)) {
+    if (hasReadableStreamBody || isReadableStream(value) || isFormData(value)) {
       readableStreamKeys.push(key);
     }
   }
diff --git a/src/cloudflare/internal/test/ai/ai-api-test.js b/src/cloudflare/internal/test/ai/ai-api-test.js
index ceea08d1761..20e2302dfe5 100644
--- a/src/cloudflare/internal/test/ai/ai-api-test.js
+++ b/src/cloudflare/internal/test/ai/ai-api-test.js
@@ -214,6 +214,25 @@ export const tests = {
       );
     }
 
+    {
+      // Test form data input
+      const form = new FormData();
+      form.append('prompt', 'cat');
+      const resp = await env.ai.run('formDataInputs', {
+        audio: {
+          body: form,
+          contentType: 'multipart/form-data',
+        },
+      });
+
+      assert.deepStrictEqual(resp, {
+        inputs: {},
+        options: { userInputs: '{}', version: '3' },
+        requestUrl:
+          'https://workers-binding.ai/run?version=3&userInputs=%7B%7D',
+      });
+    }
+
     {
       // Test gateway option
       const resp = await env.ai.run(
diff --git a/src/cloudflare/internal/test/ai/ai-mock.js b/src/cloudflare/internal/test/ai/ai-mock.js
index 2095d162967..77f29da8504 100644
--- a/src/cloudflare/internal/test/ai/ai-mock.js
+++ b/src/cloudflare/internal/test/ai/ai-mock.js
@@ -97,6 +97,19 @@ export default {
       );
     }
 
+    if (modelName === 'formDataInputs') {
+      return Response.json(
+        {
+          inputs: {},
+          options: { ...data.options },
+          requestUrl: request.url,
+        },
+        {
+          headers: respHeaders,
+        }
+      );
+    }
+
     if (modelName === 'inputErrorModel') {
       return Response.json(
         {
diff --git a/types/defines/ai.d.ts b/types/defines/ai.d.ts
index 23b648cf5c1..90a8671c162 100644
--- a/types/defines/ai.d.ts
+++ b/types/defines/ai.d.ts
@@ -5415,7 +5415,7 @@ export type AiOptions = {
    * Maximum 5 tags are allowed each request.
    * Duplicate tags will removed.
    */
-  tags: string[];
+  tags?: string[];
   gateway?: GatewayOptions;
   returnRawResponse?: boolean;
   prefix?: string;
diff --git a/types/generated-snapshot/experimental/index.d.ts b/types/generated-snapshot/experimental/index.d.ts
index 5b7541551f5..e4b5a28d60a 100755
--- a/types/generated-snapshot/experimental/index.d.ts
+++ b/types/generated-snapshot/experimental/index.d.ts
@@ -9932,7 +9932,7 @@ type AiOptions = {
    * Maximum 5 tags are allowed each request.
    * Duplicate tags will removed.
    */
-  tags: string[];
+  tags?: string[];
   gateway?: GatewayOptions;
   returnRawResponse?: boolean;
   prefix?: string;
diff --git a/types/generated-snapshot/experimental/index.ts b/types/generated-snapshot/experimental/index.ts
index 02bc0cefb20..aa8d0376387 100755
--- a/types/generated-snapshot/experimental/index.ts
+++ b/types/generated-snapshot/experimental/index.ts
@@ -9946,7 +9946,7 @@ export type AiOptions = {
    * Maximum 5 tags are allowed each request.
    * Duplicate tags will removed.
    */
-  tags: string[];
+  tags?: string[];
   gateway?: GatewayOptions;
   returnRawResponse?: boolean;
   prefix?: string;
diff --git a/types/generated-snapshot/latest/index.d.ts b/types/generated-snapshot/latest/index.d.ts
index cf4c1ef9ba0..4a7887dd6e5 100755
--- a/types/generated-snapshot/latest/index.d.ts
+++ b/types/generated-snapshot/latest/index.d.ts
@@ -9328,7 +9328,7 @@ type AiOptions = {
    * Maximum 5 tags are allowed each request.
    * Duplicate tags will removed.
    */
-  tags: string[];
+  tags?: string[];
   gateway?: GatewayOptions;
   returnRawResponse?: boolean;
   prefix?: string;
diff --git a/types/generated-snapshot/latest/index.ts b/types/generated-snapshot/latest/index.ts
index 41f1457a631..59ff5b53254 100755
--- a/types/generated-snapshot/latest/index.ts
+++ b/types/generated-snapshot/latest/index.ts
@@ -9340,7 +9340,7 @@ export type AiOptions = {
    * Maximum 5 tags are allowed each request.
    * Duplicate tags will removed.
    */
-  tags: string[];
+  tags?: string[];
   gateway?: GatewayOptions;
   returnRawResponse?: boolean;
   prefix?: string;