feat(appkit): fromPlugin() DX, runAgent plugins arg, shared toolkit-resolver

knip.json

@@ -17,16 +17,17 @@
     "**/*.css",
     "packages/appkit/src/plugins/vector-search/**",
     "packages/appkit/src/plugin/index.ts",
+    "packages/appkit/src/plugin/to-plugin.ts",
     "packages/appkit/src/plugins/agents/index.ts",
-    "template/**",
-    "tools/**",
-    "docs/**",
-    ".github/scripts/**",
+    "packages/appkit/src/core/agent/index.ts",
     "packages/appkit/src/core/agent/tools/index.ts",
     "packages/appkit/src/core/agent/from-plugin.ts",
     "packages/appkit/src/core/agent/load-agents.ts",
     "packages/appkit/src/connectors/mcp/index.ts",
-    "packages/appkit/src/plugin/to-plugin.ts"
+    "template/**",
+    "tools/**",
+    "docs/**",
+    ".github/scripts/**"
   ],
   "ignoreDependencies": ["json-schema-to-typescript"],
   "ignoreBinaries": ["tarball"]

packages/appkit/src/beta.ts

@@ -52,8 +52,10 @@ export type {
   AgentDefinition,
   AgentsPluginConfig,
   AgentTool,
+  AgentTools,
   AutoInheritToolsConfig,
   BaseSystemPromptOption,
+  FromPluginMarker,
   PromptContext,
   RegisteredAgent,
   ResolvedToolEntry,
@@ -62,6 +64,8 @@ export type {
 } from "./plugins/agents";
 export {
   agentIdFromMarkdownPath,
+  fromPlugin,
+  isFromPluginMarker,
   isToolkitEntry,
   loadAgentFromFile,
   loadAgentsFromDir,

packages/appkit/src/connectors/mcp/types.ts

@@ -1,7 +1,7 @@
 /**
  * Input shape consumed by {@link AppKitMcpClient.connect}. Produced by the
  * agents plugin from user-facing `HostedTool` declarations (see
- * `plugins/agents/tools/hosted-tools.ts`) and accepted directly by the
+ * `core/agent/tools/hosted-tools.ts`) and accepted directly by the
  * connector to keep its surface free of agent-layer concepts.
  */
 export interface McpEndpointConfig {

packages/appkit/src/core/agent/from-plugin.ts

@@ -0,0 +1,97 @@
+import type { NamedPluginFactory } from "../../plugin/to-plugin";
+import type { ToolkitOptions } from "./types";
+
+/**
+ * Symbol brand for the `fromPlugin` marker. Using a globally-interned symbol
+ * (`Symbol.for`) keeps the brand stable across module boundaries / bundle
+ * duplicates so `isFromPluginMarker` stays reliable.
+ */
+export const FROM_PLUGIN_MARKER = Symbol.for(
+  "@databricks/appkit.fromPluginMarker",
+);
+
+/**
+ * A lazy reference to a plugin's tools, produced by {@link fromPlugin} and
+ * resolved to concrete `ToolkitEntry`s at `AgentsPlugin.setup()` time.
+ *
+ * The marker is spread under a unique symbol key so multiple calls to
+ * `fromPlugin` (even for the same plugin) coexist in an `AgentDefinition.tools`
+ * record without colliding.
+ */
+export interface FromPluginMarker {
+  readonly [FROM_PLUGIN_MARKER]: true;
+  readonly pluginName: string;
+  readonly opts: ToolkitOptions | undefined;
+}
+
+/**
+ * Record shape returned by {@link fromPlugin} — a single symbol-keyed entry
+ * suitable for spreading into `AgentDefinition.tools`.
+ */
+export type FromPluginSpread = { readonly [key: symbol]: FromPluginMarker };
+
+/**
+ * Reference a plugin's tools inside an `AgentDefinition.tools` record without
+ * naming the plugin instance. The returned spread-friendly object carries a
+ * symbol-keyed marker that the agents plugin resolves against registered
+ * `ToolProvider`s at setup time.
+ *
+ * The factory argument must come from `toPlugin` (or any function that
+ * carries a `pluginName` field). `fromPlugin` reads `factory.pluginName`
+ * synchronously — it does not construct an instance.
+ *
+ * If the referenced plugin is also registered in `createApp({ plugins })`, the
+ * same runtime instance is used for dispatch. If the plugin is missing,
+ * `AgentsPlugin.setup()` throws with a clear `Available: …` listing.
+ *
+ * @example
+ * ```ts
+ * import { analytics, createAgent, files, fromPlugin, tool } from "@databricks/appkit";
+ *
+ * const support = createAgent({
+ *   instructions: "You help customers.",
+ *   tools: {
+ *     ...fromPlugin(analytics),
+ *     ...fromPlugin(files, { only: ["uploads.read"] }),
+ *     get_weather: tool({ ... }),
+ *   },
+ * });
+ * ```
+ *
+ * @param factory A plugin factory produced by `toPlugin`. Must expose a
+ *   `pluginName` field.
+ * @param opts Optional toolkit scoping — `prefix`, `only`, `except`, `rename`.
+ *   Same shape as the `.toolkit()` method.
+ */
+export function fromPlugin<F extends NamedPluginFactory>(
+  factory: F,
+  opts?: ToolkitOptions,
+): FromPluginSpread {
+  if (
+    !factory ||
+    typeof factory.pluginName !== "string" ||
+    !factory.pluginName
+  ) {
+    throw new Error(
+      "fromPlugin(): factory is missing pluginName. Pass a factory created by toPlugin().",
+    );
+  }
+  const pluginName = factory.pluginName;
+  const marker: FromPluginMarker = {
+    [FROM_PLUGIN_MARKER]: true,
+    pluginName,
+    opts,
+  };
+  return { [Symbol(`fromPlugin:${pluginName}`)]: marker };
+}
+
+/**
+ * Type guard for {@link FromPluginMarker}.
+ */
+export function isFromPluginMarker(value: unknown): value is FromPluginMarker {
+  return (
+    typeof value === "object" &&
+    value !== null &&
+    (value as Record<symbol, unknown>)[FROM_PLUGIN_MARKER] === true
+  );
+}

packages/appkit/src/core/agent/index.ts

@@ -0,0 +1,64 @@
+/**
+ * Agent runtime primitives. All framework-level agent types, tool helpers,
+ * and the standalone runner live here. The HTTP-facing `agents()` plugin in
+ * `plugins/agents/` consumes these but does not own them — peer plugins
+ * (analytics, files, genie, lakebase) can depend on this module without
+ * reaching across the sibling boundary.
+ */
+export { buildToolkitEntries } from "./build-toolkit";
+export { consumeAdapterStream } from "./consume-adapter-stream";
+export { createAgent } from "./create-agent";
+export {
+  FROM_PLUGIN_MARKER,
+  type FromPluginMarker,
+  type FromPluginSpread,
+  fromPlugin,
+  isFromPluginMarker,
+} from "./from-plugin";
+export {
+  agentIdFromMarkdownPath,
+  type LoadContext,
+  type LoadResult,
+  loadAgentFromFile,
+  loadAgentsFromDir,
+  parseFrontmatter,
+} from "./load-agents";
+export { normalizeToolResult } from "./normalize-result";
+export {
+  type RunAgentInput,
+  type RunAgentResult,
+  runAgent,
+} from "./run-agent";
+export { buildBaseSystemPrompt, composeSystemPrompt } from "./system-prompt";
+export { dispatchToolCall } from "./tool-dispatch";
+export { resolveToolkitFromProvider } from "./toolkit-resolver";
+export {
+  defineTool,
+  executeFromRegistry,
+  type FunctionTool,
+  functionToolToDefinition,
+  type HostedTool,
+  isFunctionTool,
+  isHostedTool,
+  mcpServer,
+  resolveHostedTools,
+  type ToolConfig,
+  type ToolEntry,
+  type ToolRegistry,
+  tool,
+  toolsFromRegistry,
+} from "./tools";
+export {
+  type AgentDefinition,
+  type AgentsPluginConfig,
+  type AgentTool,
+  type AgentTools,
+  type AutoInheritToolsConfig,
+  type BaseSystemPromptOption,
+  isToolkitEntry,
+  type PromptContext,
+  type RegisteredAgent,
+  type ResolvedToolEntry,
+  type ToolkitEntry,
+  type ToolkitOptions,
+} from "./types";