diff --git a/extensions/image-processing-api/functions/src/operations/genkit.ts b/extensions/image-processing-api/functions/src/operations/genkit.ts
new file mode 100644
index 00000000..b3b31108
--- /dev/null
+++ b/extensions/image-processing-api/functions/src/operations/genkit.ts
@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2016-present Invertase Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import sharp from 'sharp';
+import superstruct from 'superstruct';
+import { OperationBuilder, ValidatedOperation } from '../types';
+
+const name = 'genkit';
+
+const struct = superstruct.object({
+  operation: superstruct.literal(name),
+  prompt: superstruct.string(), // require a prompt string
+});
+
+export const operationGenkit: OperationBuilder = {
+  name,
+  struct,
+  async build(
+    operation: ValidatedOperation,
+    fileMetadata: sharp.Metadata | null,
+  ) {
+    const options = operation.options as { prompt: string };
+    // Return a custom action with the prompt parameter.
+    return [
+      {
+        method: 'genkitCall',
+        arguments: [options.prompt],
+      },
+    ];
+  },
+};
+
+// TODO: Genkit implementation
+export const callGenkit: (any) => Promise<any> = async (x: any) => x;
diff --git a/extensions/image-processing-api/functions/src/operations/index.ts b/extensions/image-processing-api/functions/src/operations/index.ts
index e1ba6e5e..90b76223 100644
--- a/extensions/image-processing-api/functions/src/operations/index.ts
+++ b/extensions/image-processing-api/functions/src/operations/index.ts
@@ -15,7 +15,7 @@
  */
 
 import { AssertionError } from 'assert';
-import sharp, { SharpOptions } from 'sharp';
+import sharp from 'sharp';
 import superstruct from 'superstruct';
 
 import { omitKey, omitUndefinedValues } from '../utils';
@@ -56,6 +56,7 @@ import { operationTint } from './tint';
 import { operationGrayScale } from './grayscale';
 import { operationModulate } from './modulate';
 import { operationLinear } from './linear';
+import { callGenkit, operationGenkit } from './genkit';
 
 export * from './input';
 export * from './output';
@@ -115,6 +116,7 @@ const builders: { [key: string]: OperationBuilder } = {
   grayscale: operationGrayScale,
   modulate: operationModulate,
   linear: operationLinear,
+  genkit: operationGenkit,
 };
 
 export function builderForOperation(operation: Operation): OperationBuilder {
@@ -259,8 +261,27 @@ export async function applyValidatedOperation(
   );
   for (let i = 0; i < builtOperation.actions.length; i++) {
     const action = builtOperation.actions[i];
+
+    // Handle our custom external API action.
+    if (action.method === 'genkitCall' && currentInstance) {
+      // Retrieve the prompt from the action arguments.
+      const promptParam = action.arguments[0];
+      const buffer = await currentInstance.toBuffer();
+      const base64Image = buffer.toString('base64');
+      // Call the external API with the image and prompt.
+      const newBase64 = await callGenkit({
+        image: base64Image,
+        prompt: promptParam,
+      });
+      const newBuffer = Buffer.from(newBase64, 'base64');
+      currentInstance = sharp(newBuffer);
+      continue;
+    }
+
     if (action.method == 'constructor') {
-      currentInstance = sharp(...(action.arguments as SharpOptions[]));
+      currentInstance = sharp(
+        ...(action.arguments as Parameters<typeof sharp>),
+      );
     } else if (currentInstance != null) {
       currentInstance = (
         currentInstance[action.method] as (...args: unknown[]) => sharp.Sharp