From fa6b90f7a8c77c2a81b1c30bb91a55fac8ad45e1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=B1=9F=E5=A4=8F=E5=B0=A7?= <3446798488@qq.com>
Date: Thu, 22 May 2025 21:18:17 +0800
Subject: [PATCH 1/2] feat(swarm): Add an optional state update function to
 support custom state updates during handover

---
 libs/langgraph-swarm/src/handoff.ts | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/libs/langgraph-swarm/src/handoff.ts b/libs/langgraph-swarm/src/handoff.ts
index 3f57ed222..6dede46fa 100644
--- a/libs/langgraph-swarm/src/handoff.ts
+++ b/libs/langgraph-swarm/src/handoff.ts
@@ -28,6 +28,7 @@ function _normalizeAgentName(agentName: string): string {
 interface CreateHandoffToolParams {
   agentName: string;
   description?: string;
+  updateState?: (state: any) => Record<string, any>;
 }
 
 // type guard
@@ -45,6 +46,7 @@ function isDynamicTool(
 const createHandoffTool = ({
   agentName,
   description,
+  updateState,
 }: CreateHandoffToolParams) => {
   /**
    * Create a tool that can handoff control to the requested agent.
@@ -56,6 +58,7 @@ const createHandoffTool = ({
    *   nodes as well as the tool names accepted by LLM providers
    *   (the tool name will look like this: `transfer_to_<agent_name>`).
    * @param description - Optional description for the handoff tool.
+   * @param updateState - Optional function to customize state updates during handoff.
    */
   const toolName = `transfer_to_${_normalizeAgentName(agentName)}`;
   const toolDescription = description || `Ask agent '${agentName}' for help`;
@@ -74,13 +77,22 @@ const createHandoffTool = ({
       // inject the current agent state
       const state =
         getCurrentTaskInput() as (typeof MessagesAnnotation)["State"];
+
+      // Base update object containing essential state updates
+      const baseUpdate = {
+        messages: state.messages.concat(toolMessage),
+        activeAgent: agentName,
+      };
+
+      // Merge custom updates with base updates if updateState function is provided
+      const finalUpdate = updateState
+        ? { ...baseUpdate, ...updateState(state) }
+        : baseUpdate;
+
       return new Command({
         goto: agentName,
         graph: Command.PARENT,
-        update: {
-          messages: state.messages.concat(toolMessage),
-          activeAgent: agentName,
-        },
+        update: finalUpdate,
       });
     },
     {

From 3eae4e79983a53c23ffee6f5a8223737f808e79e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=B1=9F=E5=A4=8F=E5=B0=A7?= <3446798488@qq.com>
Date: Thu, 22 May 2025 21:24:53 +0800
Subject: [PATCH 2/2] chore(swarm): code lint

---
 libs/langgraph-swarm/src/handoff.ts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/libs/langgraph-swarm/src/handoff.ts b/libs/langgraph-swarm/src/handoff.ts
index 6dede46fa..a82253ad1 100644
--- a/libs/langgraph-swarm/src/handoff.ts
+++ b/libs/langgraph-swarm/src/handoff.ts
@@ -28,6 +28,7 @@ function _normalizeAgentName(agentName: string): string {
 interface CreateHandoffToolParams {
   agentName: string;
   description?: string;
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
   updateState?: (state: any) => Record<string, any>;
 }