feat(appkit): supervisor api adapter

Author: hubertzub-db

apps/dev-playground/server/index.ts

@@ -14,6 +14,7 @@ import {
   tool,
   WRITE_ACTIONS,
 } from "@databricks/appkit";
+import { fromSupervisorApi } from "@databricks/appkit/agents/supervisor-api";
 import { WorkspaceClient } from "@databricks/sdk-experimental";
 import { z } from "zod";
 import { lakebaseExamples } from "./lakebase-examples-plugin";
@@ -68,6 +69,33 @@ const helper = createAgent({
   },
 });
 
+// Supervisor API demo agent. Tools are configured on the adapter (the SA
+// endpoint executes them server-side), not on the createAgent definition.
+// Uncomment a `supervisorTools.*` entry (and import 'supervisorTools' from
+// '@databricks/appkit/agents/supervisor-api') to give the model real powers.
+//
+// We `await` the factory at module init so a misconfigured workspace
+// (missing host, bad credentials) fails fast with a clear error here
+// instead of as an unhandled rejection. Top-level await is fine in this
+// ESM module.
+const supervisor = createAgent({
+  instructions:
+    "You are an assistant powered by the Databricks Supervisor API.",
+  model: fromSupervisorApi({
+    model: "databricks-claude-sonnet-4-5",
+    tools: [
+      // supervisorTools.genieSpace(
+      //   "01ABCDEF12345678",
+      //   "NYC taxi trip records and zones",
+      // ),
+      // supervisorTools.ucFunction(
+      //   "main.default.add",
+      //   "Adds two integers and returns the sum.",
+      // ),
+    ],
+  }),
+});
+
 /*
  * Smart-Dashboard agents.
  *
@@ -367,7 +395,7 @@ 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.

packages/appkit/package.json

@@ -41,6 +41,10 @@
       "development": "./src/agents/databricks.ts",
       "default": "./dist/agents/databricks.js"
     },
+    "./agents/supervisor-api": {
+      "development": "./src/agents/supervisor-api.ts",
+      "default": "./dist/agents/supervisor-api.js"
+    },
     "./type-generator": {
       "types": "./dist/type-generator/index.d.ts",
       "development": "./src/type-generator/index.ts",
@@ -126,6 +130,7 @@
       "./agents/vercel-ai": "./dist/agents/vercel-ai.js",
       "./agents/langchain": "./dist/agents/langchain.js",
       "./agents/databricks": "./dist/agents/databricks.js",
+      "./agents/supervisor-api": "./dist/agents/supervisor-api.js",
       "./dist/shared/src/plugin": "./dist/shared/src/plugin.d.ts",
       "./type-generator": "./dist/type-generator/index.js",
       "./package.json": "./package.json"

packages/appkit/src/agents/databricks.ts

@@ -6,6 +6,7 @@ import type {
   AgentToolDefinition,
 } from "shared";
 import { stream as servingStream } from "../connectors/serving/client";
+import { readSseEvents } from "../stream";
 
 /**
  * Transport shim: given an OpenAI-compatible request body, returns the raw
@@ -388,68 +389,47 @@ export class DatabricksAdapter implements AgentAdapter {
     }
 
     const responseBody = await this.streamBody(body, context.signal);
-    const reader = responseBody.getReader();
 
-    const decoder = new TextDecoder();
-    let buffer = "";
     let fullText = "";
     const toolCallAccumulator = new Map<
       number,
       { id: string; name: string; arguments: string }
     >();
 
-    try {
-      while (true) {
-        if (context.signal?.aborted) break;
+    for await (const { data } of readSseEvents(responseBody, context.signal)) {
+      if (data === "[DONE]") continue;
 
-        const { done, value } = await reader.read();
-        if (done) break;
-
-        buffer += decoder.decode(value, { stream: true });
-        const lines = buffer.split("\n");
-        buffer = lines.pop() ?? "";
-
-        for (const line of lines) {
-          const trimmed = line.trim();
-          if (!trimmed.startsWith("data: ")) continue;
-          const data = trimmed.slice(6);
-          if (data === "[DONE]") continue;
-
-          let parsed: any;
-          try {
-            parsed = JSON.parse(data);
-          } catch {
-            continue;
-          }
+      let parsed: any;
+      try {
+        parsed = JSON.parse(data);
+      } catch {
+        continue;
+      }
 
-          const delta = parsed.choices?.[0]?.delta;
-          if (!delta) continue;
+      const delta = parsed.choices?.[0]?.delta;
+      if (!delta) continue;
 
-          if (delta.content) {
-            fullText += delta.content;
-            yield { type: "message_delta" as const, content: delta.content };
-          }
+      if (delta.content) {
+        fullText += delta.content;
+        yield { type: "message_delta" as const, content: delta.content };
+      }
 
-          if (delta.tool_calls) {
-            for (const tc of delta.tool_calls as DeltaToolCall[]) {
-              const existing = toolCallAccumulator.get(tc.index);
-              if (existing) {
-                if (tc.function?.arguments) {
-                  existing.arguments += tc.function.arguments;
-                }
-              } else {
-                toolCallAccumulator.set(tc.index, {
-                  id: tc.id ?? `call_${tc.index}`,
-                  name: tc.function?.name ?? "",
-                  arguments: tc.function?.arguments ?? "",
-                });
-              }
+      if (delta.tool_calls) {
+        for (const tc of delta.tool_calls as DeltaToolCall[]) {
+          const existing = toolCallAccumulator.get(tc.index);
+          if (existing) {
+            if (tc.function?.arguments) {
+              existing.arguments += tc.function.arguments;
             }
+          } else {
+            toolCallAccumulator.set(tc.index, {
+              id: tc.id ?? `call_${tc.index}`,
+              name: tc.function?.name ?? "",
+              arguments: tc.function?.arguments ?? "",
+            });
           }
         }
       }
-    } finally {
-      reader.releaseLock();
     }
 
     const toolCalls: OpenAIToolCall[] = Array.from(