added adk docs

docs/en/samples/pre_post_processing/js.md

@@ -16,7 +16,11 @@ This guide demonstrates how to implement these patterns in your Toolbox applicat
 
 {{< tabpane persist=header >}}
 {{% tab header="ADK" text=true %}}
-Coming soon.
+The following example demonstrates how to use the `beforeToolCallback` and `afterToolCallback` hooks in the ADK `LlmAgent` to implement pre and post processing logic. Specifically, it shows how to intercept tool calls to enforce business policies (blocking invalid actions) and enrich tool outputs (adding loyalty points) before they return to the model.
+
+```js
+{{< include "js/adk/agent.js" >}}
+```
 {{% /tab %}}
 {{% tab header="Langchain" text=true %}}
 The following example demonstrates how to use `ToolboxClient` with LangChain's middleware to implement pre and post processing for tool calls.

docs/en/samples/pre_post_processing/js/adk/agent.js

@@ -0,0 +1,100 @@
+import { InMemoryRunner, LlmAgent, LogLevel } from '@google/adk';
+import { ToolboxClient } from '@toolbox-sdk/adk';
+
+const systemPrompt = `
+  You're a helpful hotel assistant. You handle hotel searching, booking and
+  cancellations. When the user searches for a hotel, mention it's name, id,
+  location and price tier. Always mention hotel ids while performing any
+  searches. This is very important for any operations. For any bookings or
+  cancellations, please provide the appropriate confirmation. Be sure to
+  update checkin or checkout dates if mentioned by the user.
+  Don't ask for confirmations from the user.
+`;
+
+/**
+ * Pre-processing: Enforce Business Rules
+ */
+function preProcess({tool, args}) {
+  const name = tool.name;
+  console.log(`POLICY CHECK: Intercepting '${name}'`);
+
+  if (name === "update-hotel" && args.checkin_date && args.checkout_date) {
+    const start = new Date(args.checkin_date);
+    const end = new Date(args.checkout_date);
+    const duration = (end - start) / (1000 * 60 * 60 * 24); // days
+
+    if (duration > 14) {
+      console.log("BLOCKED: Stay too long");
+      return "Error: Maximum stay duration is 14 days.";
+    }
+  }
+  return undefined;
+}
+
+/**
+ * Post-processing: Enrich Response
+ */
+function postProcess({tool, response}) {
+  const name = tool.name;
+  
+  let content = response;
+  if (typeof response === 'object' && response !== null) {
+      if (response.result) content = response.result;
+      else if (response.content) content = response.content;
+  }
+  if (name === "book-hotel") {
+      const loyaltyBonus = 500;
+      const enrichedContent = `Booking Confirmed!\n You earned ${loyaltyBonus} Loyalty Points with this stay.\n\nSystem Details: ${content}`;
+      if (typeof response === 'object' && response !== null) {
+          return { ...response, result: enrichedContent, content: enrichedContent };
+      }
+      return enrichedContent;
+  }
+  return response;
+}
+
+process.env.GOOGLE_GENAI_API_KEY = process.env.GOOGLE_API_KEY || 'your-api-key';
+
+async function runTurn(runner, userId, sessionId, prompt) {
+  console.log(`\nUSER: '${prompt}'`);
+  const content = { role: 'user', parts: [{ text: prompt }] };
+  const stream = runner.runAsync({ userId, sessionId, newMessage: content });
+  
+  let fullText = "";
+  for await (const chunk of stream) {
+      if (chunk.content && chunk.content.parts) {
+          fullText += chunk.content.parts.map(p => p.text || "").join("");
+      }
+  }
+  
+  console.log("-".repeat(50));
+  console.log(`AI: ${fullText}`);
+}
+
+export async function main() {
+  const userId = 'test_user';
+  const client = new ToolboxClient('http://127.0.0.1:5000');
+  const tools = await client.loadToolset("my-toolset");
+  
+  const rootAgent = new LlmAgent({
+    name: 'hotel_agent',
+    model: 'gemini-2.5-flash',
+    description: 'Agent for hotel bookings and administration.',
+    instruction: systemPrompt,
+    tools: tools,
+    beforeToolCallback: preProcess,
+    afterToolCallback: postProcess
+  });
+
+  const appName = rootAgent.name;
+  const runner = new InMemoryRunner({ agent: rootAgent, appName, logLevel: LogLevel.ERROR });
+  const session = await runner.sessionService.createSession({ appName, userId });
+
+  // Turn 1: Booking
+  await runTurn(runner, userId, session.id, "Book hotel with id 3.");
+
+  // Turn 2: Policy Violation
+  await runTurn(runner, userId, session.id, "Update my hotel with id 3 with checkin date 2025-01-18 and checkout date 2025-02-10");
+}
+
+main();

docs/en/samples/pre_post_processing/js/adk/package.json

@@ -0,0 +1,16 @@
+{
+  "name": "adk",
+  "version": "1.0.0",
+  "description": "ADK.js sample for pre/post processing",
+  "type": "module",
+  "main": "agent.js",
+  "scripts": {
+    "start": "node agent.js"
+  },
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "@google/adk": "^0.2.0",
+    "@toolbox-sdk/adk": "^0.2.1"
+  }
+}