Add example of code execution with tools reading files

Author: pokey

examples/src/createAgent/middleware/codeExecutionExtraTools.ts

@@ -0,0 +1,80 @@
+/**
+ * Example demonstrating Code Execution Middleware with additional tools.
+ *
+ * This example shows how to combine code execution capabilities with custom tools
+ * that can access files generated by code execution. The example creates an
+ * email_file tool that reads files from the agent's workspace and demonstrates
+ * how tools can interact with code execution outputs.
+ */
+
+import { ChatAnthropic } from "@langchain/anthropic";
+import { AnthropicContainerProvider } from "@langchain/anthropic/middleware";
+import { HumanMessage } from "@langchain/core/messages";
+import { getCurrentTaskInput } from "@langchain/langgraph";
+import {
+  codeExecutionMiddleware,
+  createAgent,
+  MemoryFileProvider,
+  tool,
+  type CodeExecutionMiddlewareState,
+} from "langchain";
+import fs from "node:fs/promises";
+import { z } from "zod";
+
+// Initial setup
+const model = new ChatAnthropic({
+  model: "claude-sonnet-4-5-20250929",
+});
+
+const middleware = codeExecutionMiddleware(
+  new AnthropicContainerProvider(),
+  new MemoryFileProvider()
+);
+
+const emailTool = tool(
+  async ({ path }, config) => {
+    // Access the current agent state using getCurrentTaskInput
+    const state = getCurrentTaskInput<CodeExecutionMiddlewareState>(config);
+
+    // Find the file using the middleware's files method
+    const file = middleware.files(state).find((f) => f.path === path);
+
+    if (!file) {
+      return `Error: File not found at path: ${path}`;
+    }
+
+    // Get the file content
+    const content = await file.getContent();
+
+    // Simulate emailing the file
+    console.log("Pretending to email file with content:");
+    console.log(content.toString());
+
+    return `Successfully emailed file: ${path}`;
+  },
+  {
+    name: "email_file",
+    description:
+      "Email a file by providing its path. The file must exist in the agent's workspace.",
+    schema: z.object({
+      path: z.string().describe("The path to the file to email"),
+    }),
+  }
+);
+
+const agent = createAgent({
+  model,
+  middleware: [middleware],
+  tools: [emailTool],
+});
+
+// Read and add the test data file
+const testDataPath = "test_data.csv";
+const fileContent = await fs.readFile(testDataPath);
+
+await agent.invoke({
+  messages: new HumanMessage(
+    "Turn this into a markdown file with a table and then email it."
+  ),
+  files: [await middleware.addFile(testDataPath, fileContent)],
+});