openai[minor],core[minor]: Add support for passing strict in openai tools

docs/core_docs/docs/integrations/chat/openai.ipynb

@@ -411,7 +411,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "3a5bb5ca-c3ae-4a58-be67-2cd18574b9a3",
+   "id": "bc5ecebd",
    "metadata": {},
    "source": [
     "## Tool calling\n",
@@ -420,8 +420,82 @@
     "\n",
     "- [How to: disable parallel tool calling](/docs/how_to/tool_calling_parallel/)\n",
     "- [How to: force a tool call](/docs/how_to/tool_choice/)\n",
-    "- [How to: bind model-specific tool formats to a model](/docs/how_to/tool_calling#binding-model-specific-formats-advanced).\n",
+    "- [How to: bind model-specific tool formats to a model](/docs/how_to/tool_calling#binding-model-specific-formats-advanced)."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "3392390e",
+   "metadata": {},
+   "source": [
+    "### ``strict: true``\n",
+    "\n",
+    "```{=mdx}\n",
+    "\n",
+    ":::info Requires ``@langchain/openai >= 0.2.6``\n",
+    "\n",
+    "As of Aug 6, 2024, OpenAI supports a `strict` argument when calling tools that will enforce that the tool argument schema is respected by the model. See more here: https://platform.openai.com/docs/guides/function-calling\n",
+    "\n",
+    "**Note**: If ``strict: true`` the tool definition will also be validated, and a subset of JSON schema are accepted. Crucially, schema cannot have optional args (those with default values). Read the full docs on what types of schema are supported here: https://platform.openai.com/docs/guides/structured-outputs/supported-schemas. \n",
+    ":::\n",
+    "\n",
+    "\n",
+    "```"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "id": "90f0d465",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[\n",
+      "  {\n",
+      "    name: 'get_current_weather',\n",
+      "    args: { location: 'Hanoi' },\n",
+      "    type: 'tool_call',\n",
+      "    id: 'call_aB85ybkLCoccpzqHquuJGH3d'\n",
+      "  }\n",
+      "]\n"
+     ]
+    }
+   ],
+   "source": [
+    "import { ChatOpenAI } from \"@langchain/openai\";\n",
+    "import { tool } from \"@langchain/core/tools\";\n",
+    "import { z } from \"zod\";\n",
+    "\n",
+    "const weatherTool = tool((_) => \"no-op\", {\n",
+    "  name: \"get_current_weather\",\n",
+    "  description: \"Get the current weather\",\n",
+    "  schema: z.object({\n",
+    "    location: z.string(),\n",
+    "  }),\n",
+    "})\n",
+    "\n",
+    "const llmWithStrictTrue = new ChatOpenAI({\n",
+    "  model: \"gpt-4o\",\n",
+    "}).bindTools([weatherTool], {\n",
+    "  strict: true,\n",
+    "  tool_choice: weatherTool.name,\n",
+    "});\n",
+    "\n",
+    "// Although the question is not about the weather, it will call the tool with the correct arguments\n",
+    "// because we passed `tool_choice` and `strict: true`.\n",
+    "const strictTrueResult = await llmWithStrictTrue.invoke(\"What is 127862 times 12898 divided by 2?\");\n",
     "\n",
+    "console.dir(strictTrueResult.tool_calls, { depth: null });"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "3a5bb5ca-c3ae-4a58-be67-2cd18574b9a3",
+   "metadata": {},
+   "source": [
     "## API reference\n",
     "\n",
     "For detailed documentation of all ChatOpenAI features and configurations head to the API reference: https://api.js.langchain.com/classes/langchain_openai.ChatOpenAI.html"

langchain-core/src/language_models/base.ts

@@ -233,6 +233,15 @@ export interface FunctionDefinition {
    * how to call the function.
    */
   description?: string;
+
+  /**
+   * Whether to enable strict schema adherence when generating the function call. If
+   * set to true, the model will follow the exact schema defined in the `parameters`
+   * field. Only a subset of JSON Schema is supported when `strict` is `true`. Learn
+   * more about Structured Outputs in the
+   * [function calling guide](https://platform.openai.com/docs/guides/function-calling).
+   */
+  strict?: boolean;
 }
 
 export interface ToolDefinition {

langchain-core/src/utils/function_calling.ts

@@ -13,12 +13,26 @@ import { Runnable, RunnableToolLike } from "../runnables/base.js";
  * @returns {FunctionDefinition} The inputted tool in OpenAI function format.
  */
 export function convertToOpenAIFunction(
-  tool: StructuredToolInterface | RunnableToolLike
+  tool: StructuredToolInterface | RunnableToolLike,
+  fields?:
+    | {
+        /**
+         * If `true`, model output is guaranteed to exactly match the JSON Schema
+         * provided in the function definition.
+         */
+        strict?: boolean;
+      }
+    | number
 ): FunctionDefinition {
+  // @TODO 0.3.0 Remove the `number` typing
+  const fieldsCopy = typeof fields === "number" ? undefined : fields;
+
   return {
     name: tool.name,
     description: tool.description,
     parameters: zodToJsonSchema(tool.schema),
+    // Do not include the `strict` field if it is `undefined`.
+    ...(fieldsCopy?.strict !== undefined ? { strict: fieldsCopy.strict } : {}),
   };
 }
 
@@ -34,15 +48,35 @@ export function convertToOpenAIFunction(
  */
 export function convertToOpenAITool(
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  tool: StructuredToolInterface | Record<string, any> | RunnableToolLike
+  tool: StructuredToolInterface | Record<string, any> | RunnableToolLike,
+  fields?:
+    | {
+        /**
+         * If `true`, model output is guaranteed to exactly match the JSON Schema
+         * provided in the function definition.
+         */
+        strict?: boolean;
+      }
+    | number
 ): ToolDefinition {
-  if (isStructuredTool(tool) || isRunnableToolLike(tool)) {
-    return {
+  // @TODO 0.3.0 Remove the `number` typing
+  const fieldsCopy = typeof fields === "number" ? undefined : fields;
+
+  let toolDef: ToolDefinition | undefined;
+  if (isLangChainTool(tool)) {
+    toolDef = {
       type: "function",
       function: convertToOpenAIFunction(tool),
     };
+  } else {
+    toolDef = tool as ToolDefinition;
+  }
+
+  if (fieldsCopy?.strict !== undefined) {
+    toolDef.function.strict = fieldsCopy.strict;
   }
-  return tool as ToolDefinition;
+
+  return toolDef;
 }
 
 /**
@@ -76,3 +110,21 @@ export function isRunnableToolLike(tool?: unknown): tool is RunnableToolLike {
     tool.constructor.lc_name() === "RunnableToolLike"
   );
 }
+
+/**
+ * Whether or not the tool is one of StructuredTool, RunnableTool or StructuredToolParams.
+ * It returns `is StructuredToolParams` since that is the most minimal interface of the three,
+ * while still containing the necessary properties to be passed to a LLM for tool calling.
+ *
+ * @param {unknown | undefined} tool The tool to check if it is a LangChain tool.
+ * @returns {tool is StructuredToolParams} Whether the inputted tool is a LangChain tool.
+ */
+export function isLangChainTool(
+  tool?: unknown
+): tool is StructuredToolInterface {
+  return (
+    isRunnableToolLike(tool) ||
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    isStructuredTool(tool as any)
+  );
+}

langchain/src/agents/openai_tools/index.ts

@@ -116,7 +116,9 @@ export async function createOpenAIToolsAgent({
       ].join("\n")
     );
   }
-  const modelWithTools = llm.bind({ tools: tools.map(convertToOpenAITool) });
+  const modelWithTools = llm.bind({
+    tools: tools.map((tool) => convertToOpenAITool(tool)),
+  });
   const agent = AgentRunnableSequence.fromRunnables(
     [
       RunnablePassthrough.assign({

langchain/src/agents/openai_tools/output_parser.ts

@@ -30,7 +30,7 @@ export type { ToolsAgentAction, ToolsAgentStep };
  *   new ChatOpenAI({
  *     modelName: "gpt-3.5-turbo-1106",
  *     temperature: 0,
- *   }).bind({ tools: tools.map(convertToOpenAITool) }),
+ *   }).bind({ tools: tools.map((tool) => convertToOpenAITool(tool)) }),
  *   new OpenAIToolsAgentOutputParser(),
  * ]).withConfig({ runName: "OpenAIToolsAgent" });
  *

libs/langchain-groq/src/chat_models.ts

@@ -437,7 +437,7 @@ export class ChatGroq extends BaseChatModel<
     kwargs?: Partial<ChatGroqCallOptions>
   ): Runnable<BaseLanguageModelInput, AIMessageChunk, ChatGroqCallOptions> {
     return this.bind({
-      tools: tools.map(convertToOpenAITool),
+      tools: tools.map((tool) => convertToOpenAITool(tool)),
       ...kwargs,
     });
   }

libs/langchain-ollama/src/chat_models.ts

@@ -298,7 +298,7 @@ export class ChatOllama
     kwargs?: Partial<this["ParsedCallOptions"]>
   ): Runnable<BaseLanguageModelInput, AIMessageChunk, ChatOllamaCallOptions> {
     return this.bind({
-      tools: tools.map(convertToOpenAITool),
+      tools: tools.map((tool) => convertToOpenAITool(tool)),
       ...kwargs,
     });
   }
@@ -359,7 +359,9 @@ export class ChatOllama
         stop: options?.stop,
       },
       tools: options?.tools?.length
-        ? (options.tools.map(convertToOpenAITool) as OllamaTool[])
+        ? (options.tools.map((tool) =>
+            convertToOpenAITool(tool)
+          ) as OllamaTool[])
         : undefined,
     };
   }

libs/langchain-openai/package.json

@@ -37,7 +37,7 @@
   "dependencies": {
     "@langchain/core": ">=0.2.16 <0.3.0",
     "js-tiktoken": "^1.0.12",
-    "openai": "^4.49.1",
+    "openai": "^4.55.0",
     "zod": "^3.22.4",
     "zod-to-json-schema": "^3.22.3"
   },