refactor(appkit): restructure supervisor-api adapter per PR databricks#345 review

apps/dev-playground/server/index.ts

@@ -11,7 +11,12 @@ import {
   serving,
   WRITE_ACTIONS,
 } from "@databricks/appkit";
-import { agents, createAgent, tool } from "@databricks/appkit/beta";
+import {
+  agents,
+  createAgent,
+  DatabricksAdapter,
+  tool,
+} from "@databricks/appkit/beta";
 import { WorkspaceClient } from "@databricks/sdk-experimental";
 import { z } from "zod";
 import { lakebaseExamples } from "./lakebase-examples-plugin";
@@ -68,6 +73,35 @@ const helper = createAgent({
   },
 });
 
+// Supervisor API demo agent. The Databricks AI Gateway executes hosted
+// tools server-side; declare them via `createAgent({ tools })` like any
+// other agent tool — the agents plugin classifies the tagged record and
+// routes it to the adapter via AgentInput.extensions. Import
+// `supervisorTools` from '@databricks/appkit/beta' and uncomment an
+// entry below to give the model real powers.
+//
+// `createAgent({ model })` accepts an adapter promise, so the factory's
+// host/credential resolution is awaited lazily on first dispatch (via
+// `resolveAdapter` in the agents plugin). A misconfigured workspace will
+// surface at first chat request, not at module init.
+const supervisor = createAgent({
+  instructions:
+    "You are an assistant powered by the Databricks Supervisor API.",
+  model: DatabricksAdapter.fromSupervisorApi({
+    model: "databricks-claude-sonnet-4-5",
+  }),
+  tools: () => ({
+    // nyc: supervisorTools.genieSpace({
+    //   id: "01ABCDEF12345678",
+    //   description: "NYC taxi trip records and zones",
+    // }),
+    // add: supervisorTools.ucFunction({
+    //   name: "main.default.add",
+    //   description: "Adds two integers and returns the sum.",
+    // }),
+  }),
+});
+
 /*
  * Smart-Dashboard agents.
  *
@@ -385,7 +419,7 @@ createApp({
     }),
     serving(),
     agents({
-      agents: { helper, sql_analyst, dashboard_pilot },
+      agents: { helper, sql_analyst, dashboard_pilot, supervisor },
       // `query` (markdown dispatcher) + `sql_analyst` + `dashboard_pilot`
       // wire the /smart-dashboard route. `insights` and `anomaly` are
       // ephemeral markdown agents auto-fired by the route's AgentSidebar.