feat: deprecate Agent Chain functionality and update related methods for improved clarity

api/server/controllers/agents/callbacks.js

@@ -95,6 +95,19 @@ class ModelEndHandler {
   }
 }
 
+/**
+ * @deprecated Agent Chain helper
+ * @param {string | undefined} [last_agent_id]
+ * @param {string | undefined} [langgraph_node]
+ * @returns {boolean}
+ */
+function checkIfLastAgent(last_agent_id, langgraph_node) {
+  if (!last_agent_id || !langgraph_node) {
+    return false;
+  }
+  return langgraph_node?.endsWith(last_agent_id);
+}
+
 /**
  * Get default handlers for stream events.
  * @param {Object} options - The options object.
@@ -125,7 +138,7 @@ function getDefaultHandlers({ res, aggregateContent, toolEndCallback, collectedU
       handle: (event, data, metadata) => {
         if (data?.stepDetails.type === StepTypes.TOOL_CALLS) {
           sendEvent(res, { event, data });
-        } else if (metadata?.last_agent_index === metadata?.agent_index) {
+        } else if (checkIfLastAgent(metadata?.last_agent_id, metadata?.langgraph_node)) {
           sendEvent(res, { event, data });
         } else if (!metadata?.hide_sequential_outputs) {
           sendEvent(res, { event, data });
@@ -154,7 +167,7 @@ function getDefaultHandlers({ res, aggregateContent, toolEndCallback, collectedU
       handle: (event, data, metadata) => {
         if (data?.delta.type === StepTypes.TOOL_CALLS) {
           sendEvent(res, { event, data });
-        } else if (metadata?.last_agent_index === metadata?.agent_index) {
+        } else if (checkIfLastAgent(metadata?.last_agent_id, metadata?.langgraph_node)) {
           sendEvent(res, { event, data });
         } else if (!metadata?.hide_sequential_outputs) {
           sendEvent(res, { event, data });
@@ -172,7 +185,7 @@ function getDefaultHandlers({ res, aggregateContent, toolEndCallback, collectedU
       handle: (event, data, metadata) => {
         if (data?.result != null) {
           sendEvent(res, { event, data });
-        } else if (metadata?.last_agent_index === metadata?.agent_index) {
+        } else if (checkIfLastAgent(metadata?.last_agent_id, metadata?.langgraph_node)) {
           sendEvent(res, { event, data });
         } else if (!metadata?.hide_sequential_outputs) {
           sendEvent(res, { event, data });
@@ -188,7 +201,7 @@ function getDefaultHandlers({ res, aggregateContent, toolEndCallback, collectedU
        * @param {GraphRunnableConfig['configurable']} [metadata] The runnable metadata.
        */
       handle: (event, data, metadata) => {
-        if (metadata?.last_agent_index === metadata?.agent_index) {
+        if (checkIfLastAgent(metadata?.last_agent_id, metadata?.langgraph_node)) {
           sendEvent(res, { event, data });
         } else if (!metadata?.hide_sequential_outputs) {
           sendEvent(res, { event, data });
@@ -204,7 +217,7 @@ function getDefaultHandlers({ res, aggregateContent, toolEndCallback, collectedU
        * @param {GraphRunnableConfig['configurable']} [metadata] The runnable metadata.
        */
       handle: (event, data, metadata) => {
-        if (metadata?.last_agent_index === metadata?.agent_index) {
+        if (checkIfLastAgent(metadata?.last_agent_id, metadata?.langgraph_node)) {
           sendEvent(res, { event, data });
         } else if (!metadata?.hide_sequential_outputs) {
           sendEvent(res, { event, data });

api/server/controllers/agents/client.js

@@ -867,6 +867,9 @@ class AgentClient extends BaseClient {
         if (userMCPAuthMap != null) {
           config.configurable.userMCPAuthMap = userMCPAuthMap;
         }
+
+        /** @deprecated Agent Chain */
+        config.configurable.last_agent_id = agents[agents.length - 1].id;
         await run.processStream({ messages }, config, {
           callbacks: {
             [Callback.TOOL_ERROR]: logToolError,
@@ -877,6 +880,20 @@ class AgentClient extends BaseClient {
       };
 
       await runAgents(initialMessages);
+      /** @deprecated Agent Chain */
+      if (config.configurable.hide_sequential_outputs) {
+        this.contentParts = this.contentParts.filter((part, index) => {
+          // Include parts that are either:
+          // 1. At or after the finalContentStart index
+          // 2. Of type tool_call
+          // 3. Have tool_call_ids property
+          return (
+            index >= this.contentParts.length - 1 ||
+            part.type === ContentTypes.TOOL_CALL ||
+            part.tool_call_ids
+          );
+        });
+      }
 
       try {
         const attachments = await this.awaitMemoryWithTimeout(memoryPromise);

api/server/services/Endpoints/agents/initialize.js

@@ -192,6 +192,7 @@ const initializeClient = async ({ req, res, signal, endpointOption }) => {
     }
   }
 
+  /** @deprecated Agent Chain */
   if (agent_ids?.length) {
     for (const agentId of agent_ids) {
       if (checkAgentInit(agentId)) {

packages/api/src/agents/chain.ts

@@ -7,6 +7,7 @@ const DEFAULT_PROMPT_TEMPLATE = `Based on the following conversation and analysi
 /**
  * Helper function to create sequential chain edges with buffer string prompts
  *
+ * @deprecated Agent Chain helper
  * @param agentIds - Array of agent IDs in order of execution
  * @param promptTemplate - Optional prompt template string; defaults to a predefined template if not provided
  * @returns Array of edges configured for sequential chain with buffer prompts