Merge pull request #72 from langchain-ai/dqbd/compiled-subagent

feat: add CompiledSubAgent back

Author: dqbd

.changeset/funky-fans-notice.md

@@ -0,0 +1,5 @@
+---
+"deepagents": minor
+---
+
+Add CompiledSubAgent back to `createDeepAgent`

src/agent.ts

@@ -24,6 +24,7 @@ import {
 import { StateBackend, type BackendProtocol } from "./backends/index.js";
 import { InteropZodObject } from "@langchain/core/utils/types";
 import { AnnotationRoot } from "@langchain/langgraph";
+import { CompiledSubAgent } from "./middleware/subagents.js";
 
 /**
  * Configuration parameters for creating a Deep Agent
@@ -43,7 +44,7 @@ export interface CreateDeepAgentParams<
   /** Custom middleware to apply after standard middleware */
   middleware?: AgentMiddleware[];
   /** List of subagent specifications for task delegation */
-  subagents?: SubAgent[];
+  subagents?: (SubAgent | CompiledSubAgent)[];
   /** Structured output response format for the agent */
   responseFormat?: any; // ResponseFormat type is complex, using any for now
   /** Optional schema for context (not persisted between invocations) */

src/index.ts

@@ -15,6 +15,7 @@ export {
   type FilesystemMiddlewareOptions,
   type SubAgentMiddlewareOptions,
   type SubAgent,
+  type CompiledSubAgent,
   type FileData,
 } from "./middleware/index.js";
 

src/middleware/index.ts

@@ -7,5 +7,6 @@ export {
   createSubAgentMiddleware,
   type SubAgentMiddlewareOptions,
   type SubAgent,
+  type CompiledSubAgent,
 } from "./subagents.js";
 export { createPatchToolCallsMiddleware } from "./patch_tool_calls.js";

src/middleware/subagents.ts

@@ -170,6 +170,18 @@ When NOT to use the task tool:
 - Remember to use the \`task\` tool to silo independent tasks within a multi-part objective.
 - You should use the \`task\` tool whenever you have a complex task that will take multiple steps, and is independent from other tasks that the agent needs to complete. These agents are highly competent and efficient.`;
 
+/**
+ * Type definitions for pre-compiled agents.
+ */
+export interface CompiledSubAgent {
+  /** The name of the agent */
+  name: string;
+  /** The description of the agent */
+  description: string;
+  /** The agent instance */
+  runnable: ReactAgent<any, any, any, any> | Runnable;
+}
+
 /**
  * Type definitions for subagents
  */
@@ -238,7 +250,7 @@ function getSubagents(options: {
   defaultTools: StructuredTool[];
   defaultMiddleware: AgentMiddleware[] | null;
   defaultInterruptOn: Record<string, boolean | InterruptOnConfig> | null;
-  subagents: Array<SubAgent>;
+  subagents: (SubAgent | CompiledSubAgent)[];
   generalPurposeAgent: boolean;
 }): {
   agents: Record<string, ReactAgent<any, any, any, any> | Runnable>;
@@ -285,19 +297,24 @@ function getSubagents(options: {
       `- ${agentParams.name}: ${agentParams.description}`,
     );
 
-    const middleware = agentParams.middleware
-      ? [...defaultSubagentMiddleware, ...agentParams.middleware]
-      : [...defaultSubagentMiddleware];
-
-    const interruptOn = agentParams.interruptOn || defaultInterruptOn;
-    if (interruptOn) middleware.push(humanInTheLoopMiddleware({ interruptOn }));
-
-    agents[agentParams.name] = createAgent({
-      model: agentParams.model ?? defaultModel,
-      systemPrompt: agentParams.systemPrompt,
-      tools: agentParams.tools ?? defaultTools,
-      middleware,
-    });
+    if ("runnable" in agentParams) {
+      agents[agentParams.name] = agentParams.runnable;
+    } else {
+      const middleware = agentParams.middleware
+        ? [...defaultSubagentMiddleware, ...agentParams.middleware]
+        : [...defaultSubagentMiddleware];
+
+      const interruptOn = agentParams.interruptOn || defaultInterruptOn;
+      if (interruptOn)
+        middleware.push(humanInTheLoopMiddleware({ interruptOn }));
+
+      agents[agentParams.name] = createAgent({
+        model: agentParams.model ?? defaultModel,
+        systemPrompt: agentParams.systemPrompt,
+        tools: agentParams.tools ?? defaultTools,
+        middleware,
+      });
+    }
   }
 
   return { agents, descriptions: subagentDescriptions };
@@ -311,7 +328,7 @@ function createTaskTool(options: {
   defaultTools: StructuredTool[];
   defaultMiddleware: AgentMiddleware[] | null;
   defaultInterruptOn: Record<string, boolean | InterruptOnConfig> | null;
-  subagents: Array<SubAgent>;
+  subagents: (SubAgent | CompiledSubAgent)[];
   generalPurposeAgent: boolean;
   taskDescription: string | null;
 }) {
@@ -406,7 +423,7 @@ export interface SubAgentMiddlewareOptions {
   /** The tool configs for the default general-purpose subagent */
   defaultInterruptOn?: Record<string, boolean | InterruptOnConfig> | null;
   /** A list of additional subagents to provide to the agent */
-  subagents?: Array<SubAgent>;
+  subagents?: (SubAgent | CompiledSubAgent)[];
   /** Full system prompt override */
   systemPrompt?: string | null;
   /** Whether to include the general-purpose agent */

tests/integration/subagents.test.ts

@@ -258,6 +258,45 @@ describe("Subagent Middleware Integration Tests", () => {
     },
   );
 
+  it.concurrent(
+    "should use pre-compiled subagent",
+    { timeout: 60000 },
+    async () => {
+      const customSubagent = createAgent({
+        model: SAMPLE_MODEL,
+        systemPrompt: "Use the get_weather tool to get the weather in a city.",
+        tools: [getWeather],
+      });
+
+      const agent = createAgent({
+        model: SAMPLE_MODEL,
+        systemPrompt: "Use the task tool to call a subagent.",
+        middleware: [
+          createSubAgentMiddleware({
+            defaultModel: SAMPLE_MODEL,
+            defaultTools: [],
+            subagents: [
+              {
+                name: "weather",
+                description: "This subagent can get weather in cities.",
+                runnable: customSubagent,
+              },
+            ],
+          }),
+        ],
+      });
+
+      const expectedToolCalls = [
+        { name: "task", args: { subagent_type: "weather" } },
+        { name: "get_weather" },
+      ];
+
+      await assertExpectedSubgraphActions(expectedToolCalls, agent, {
+        messages: [new HumanMessage("What is the weather in Tokyo?")],
+      });
+    },
+  );
+
   it.concurrent(
     "should handle multiple subagents without middleware accumulation",
     { timeout: 120000 },