feat: allow defining LangChain-style tools with JSONSchema (#7973)

Author: benjamincburns

docs/core_docs/scripts/code-block-loader.js

@@ -31,7 +31,7 @@ const SYMBOL_EDGE_CASE_MAP = {
     originalSource: "@langchain/core/messages/tool",
     originalSymbolName: null,
   },
-  zodToGeminiParameters: {
+  schemaToGeminiParameters: {
     sources: ["@langchain/google-vertexai/utils"],
     originalSource: "@langchain/google-common",
     originalSymbolName: null,

examples/src/models/chat/integration_googlevertexai-tools.ts

@@ -1,6 +1,6 @@
 import { ChatVertexAI } from "@langchain/google-vertexai";
 import { type GeminiTool } from "@langchain/google-vertexai/types";
-import { zodToGeminiParameters } from "@langchain/google-vertexai/utils";
+import { schemaToGeminiParameters } from "@langchain/google-vertexai/utils";
 import { z } from "zod";
 // Or, if using the web entrypoint:
 // import { ChatVertexAI } from "@langchain/google-vertexai-web";
@@ -18,7 +18,7 @@ const geminiCalculatorTool: GeminiTool = {
     {
       name: "calculator",
       description: "A simple calculator tool",
-      parameters: zodToGeminiParameters(calculatorSchema),
+      parameters: schemaToGeminiParameters(calculatorSchema),
     },
   ],
 };

examples/src/models/chat/ollama_functions/extraction.ts

@@ -32,10 +32,7 @@ const model = new OllamaFunctions({
     {
       name: "information_extraction",
       description: "Extracts the relevant information from the passage.",
-      parameters: {
-        type: "object",
-        properties: zodToJsonSchema(schema),
-      },
+      parameters: zodToJsonSchema(schema),
     },
   ],
   function_call: {

langchain-core/src/language_models/base.ts

@@ -19,6 +19,7 @@ import { AsyncCaller, AsyncCallerParams } from "../utils/async_caller.js";
 import { encodingForModel } from "../utils/tiktoken.js";
 import { Runnable, type RunnableInterface } from "../runnables/base.js";
 import { RunnableConfig } from "../runnables/config.js";
+import { JSONSchema } from "../utils/json_schema.js";
 
 // https://www.npmjs.com/package/js-tiktoken
 
@@ -226,7 +227,7 @@ export interface FunctionDefinition {
    * To describe a function that accepts no parameters, provide the value
    * `{"type": "object", "properties": {}}`.
    */
-  parameters: Record<string, unknown>;
+  parameters: Record<string, unknown> | JSONSchema;
 
   /**
    * A description of what the function does, used by the model to choose when and