From a8f525554ccce45519eb815778a0c96d487a2418 Mon Sep 17 00:00:00 2001
From: Aarav Mittal <137450929+a2105z@users.noreply.github.com>
Date: Thu, 30 Jul 2026 17:39:54 +0000
Subject: [PATCH] fix(js/core): allow Gemini propertyOrdering in schema
 validation

Register the non-standard propertyOrdering keyword with Ajv so structured
output schemas that include Gemini field-order hints no longer fail to compile.
---
 js/core/src/schema.ts        |  4 +++
 js/core/tests/schema_test.ts | 53 ++++++++++++++++++++++++++++++++++++
 2 files changed, 57 insertions(+)

diff --git a/js/core/src/schema.ts b/js/core/src/schema.ts
index 67a0e8f0c1..7e799732c7 100644
--- a/js/core/src/schema.ts
+++ b/js/core/src/schema.ts
@@ -25,6 +25,10 @@ import { GenkitError } from './error.js';
 import type { Registry } from './registry.js';
 const ajv = new Ajv();
 addFormats(ajv);
+// Gemini structured output uses the non-standard `propertyOrdering` keyword as a
+// field-order hint. Register it so Ajv strict mode does not reject those schemas.
+// See https://ai.google.dev/gemini-api/docs/structured-output#property-ordering
+ajv.addVocabulary(['propertyOrdering']);
 
 export { z }; // provide a consistent zod to use throughout genkit
 
diff --git a/js/core/tests/schema_test.ts b/js/core/tests/schema_test.ts
index bf359a5b1a..272e13acf6 100644
--- a/js/core/tests/schema_test.ts
+++ b/js/core/tests/schema_test.ts
@@ -105,6 +105,38 @@ describe('validate()', () => {
         { path: '(root)', message: "must have required property 'foo'" },
       ],
     },
+    {
+      it: 'should allow Gemini propertyOrdering keyword in json schema',
+      jsonSchema: {
+        type: 'object',
+        properties: {
+          answer: { type: 'number' },
+          x: { type: 'number' },
+          y: { type: 'number' },
+        },
+        required: ['x', 'y', 'answer'],
+        propertyOrdering: ['x', 'y', 'answer'],
+        additionalProperties: false,
+      },
+      data: { x: 1, y: 2, answer: 3 },
+      valid: true,
+    },
+    {
+      it: 'should still validate data when propertyOrdering is present',
+      jsonSchema: {
+        type: 'object',
+        properties: {
+          x: { type: 'number' },
+          y: { type: 'number' },
+        },
+        required: ['x', 'y'],
+        propertyOrdering: ['x', 'y'],
+        additionalProperties: false,
+      },
+      data: { x: 'nope', y: 2 },
+      valid: false,
+      errors: [{ path: 'x', message: 'must be number' }],
+    },
   ];
   for (const test of tests) {
     it(test.it, () => {
@@ -375,6 +407,27 @@ describe('disableSchemaCodeGeneration()', () => {
     assert.strictEqual(result.valid, true);
   });
 
+  it('should allow Gemini propertyOrdering keyword in interpret mode', () => {
+    disableSchemaCodeGeneration();
+    const result = validateSchema(
+      { x: 1, y: 2, answer: 3 },
+      {
+        jsonSchema: {
+          type: 'object',
+          properties: {
+            answer: { type: 'number' },
+            x: { type: 'number' },
+            y: { type: 'number' },
+          },
+          required: ['x', 'y', 'answer'],
+          propertyOrdering: ['x', 'y', 'answer'],
+          additionalProperties: false,
+        },
+      }
+    );
+    assert.strictEqual(result.valid, true);
+  });
+
   it('should strip undefined values recursively', () => {
     disableSchemaCodeGeneration();
     const result = validateSchema(