google-common[patch]: Zod to Gemini params conversion when the schema contains arrays of items (#5553)

* Fix: [libs/langchain-google-common] already existing utils test

* Fix: [lib/langchain-google-common] Add failing test for arrays containing additional properties

* Fix: [lib/langchain-google-common] Fix failing test

* Update int test

* lint

---------

Co-authored-by: jacoblee93 <[email protected]>

Author: miguelff

libs/langchain-google-common/src/tests/utils.test.ts

@@ -1,3 +1,4 @@
+/* eslint-disable @typescript-eslint/no-explicit-any */
 import { expect, test } from "@jest/globals";
 import { z } from "zod";
 import { zodToGeminiParameters } from "../utils/zod_to_gemini_parameters.js";
@@ -18,7 +19,7 @@ test("zodToGeminiParameters can convert zod schema to gemini schema", () => {
 
   expect(convertedSchema.type).toBe("object");
   expect(convertedSchema.description).toBe("A simple calculator tool");
-  expect(convertedSchema).not.toContain("additionalProperties");
+  expect((convertedSchema as any).additionalProperties).toBeUndefined();
   expect(convertedSchema.properties).toEqual({
     operation: {
       type: "string",
@@ -45,3 +46,37 @@ test("zodToGeminiParameters can convert zod schema to gemini schema", () => {
     "childObject",
   ]);
 });
+
+test("zodToGeminiParameters removes additional properties from arrays", () => {
+  const zodSchema = z
+    .object({
+      people: z
+        .object({
+          name: z.string().describe("The name of a person"),
+        })
+        .array()
+        .describe("person elements"),
+    })
+    .describe("A list of people");
+
+  const convertedSchema = zodToGeminiParameters(zodSchema);
+  expect(convertedSchema.type).toBe("object");
+  expect(convertedSchema.description).toBe("A list of people");
+  expect((convertedSchema as any).additionalProperties).toBeUndefined();
+
+  const peopleSchema = convertedSchema?.properties?.people;
+  expect(peopleSchema).not.toBeUndefined();
+
+  if (peopleSchema !== undefined) {
+    expect(peopleSchema.type).toBe("array");
+    expect((peopleSchema as any).additionalProperties).toBeUndefined();
+    expect(peopleSchema.description).toBe("person elements");
+  }
+
+  const arrayItemsSchema = peopleSchema?.items;
+  expect(arrayItemsSchema).not.toBeUndefined();
+  if (arrayItemsSchema !== undefined) {
+    expect(arrayItemsSchema.type).toBe("object");
+    expect((arrayItemsSchema as any).additionalProperties).toBeUndefined();
+  }
+});

libs/langchain-google-common/src/types.ts

@@ -295,6 +295,7 @@ export type GeminiJsonSchema = Record<string, unknown> & {
 };
 
 export interface GeminiJsonSchemaDirty extends GeminiJsonSchema {
+  items?: GeminiJsonSchemaDirty;
   properties?: Record<string, GeminiJsonSchemaDirty>;
   additionalProperties?: boolean;
 }

libs/langchain-google-common/src/utils/zod_to_gemini_parameters.ts

@@ -19,6 +19,9 @@ function removeAdditionalProperties(
     const keys = Object.keys(updatedSchema.properties);
     removeProperties(updatedSchema.properties, keys, 0);
   }
+  if (Object.hasOwn(updatedSchema, "items") && updatedSchema.items) {
+    updatedSchema.items = removeAdditionalProperties(updatedSchema.items);
+  }
 
   return updatedSchema;
 }

libs/langchain-google-vertexai-web/src/tests/chat_models.int.test.ts

@@ -18,7 +18,9 @@ import { ChatVertexAI } from "../chat_models.js";
 
 class WeatherTool extends StructuredTool {
   schema = z.object({
-    location: z.string().describe("The name of city to get the weather for."),
+    locations: z
+      .array(z.object({ name: z.string() }))
+      .describe("The name of cities to get the weather for."),
   });
 
   description =
@@ -28,7 +30,7 @@ class WeatherTool extends StructuredTool {
 
   async _call(input: z.infer<typeof this.schema>) {
     console.log(`WeatherTool called with input: ${input}`);
-    return `The weather in ${input.location} is 25°C`;
+    return `The weather in ${JSON.stringify(input.locations)} is 25°C`;
   }
 }
 
@@ -128,7 +130,7 @@ describe("Google APIKey Chat", () => {
 
   test("Tool call", async () => {
     const chat = new ChatVertexAI().bindTools([new WeatherTool()]);
-    const res = await chat.invoke("What is the weather in SF");
+    const res = await chat.invoke("What is the weather in SF and LA");
     console.log(res);
     expect(res.tool_calls?.length).toEqual(1);
     expect(res.tool_calls?.[0].args).toEqual(