fix(langchain): revert conditional edge from tools to end (#33520) (#33539)

This is causing an issue with one of the middlewares

Author: eyurtsev

libs/langchain_v1/langchain/agents/factory.py

@@ -1225,15 +1225,6 @@ async def amodel_node(state: AgentState, runtime: Runtime[ContextT]) -> dict[str
     graph.add_edge(START, entry_node)
     # add conditional edges only if tools exist
     if tool_node is not None:
-        # Only include exit_node in destinations if any tool has return_direct=True
-        # or if there are structured output tools
-        tools_to_model_destinations = [loop_entry_node]
-        if (
-            any(tool.return_direct for tool in tool_node.tools_by_name.values())
-            or structured_output_tools
-        ):
-            tools_to_model_destinations.append(exit_node)
-
         graph.add_conditional_edges(
             "tools",
             _make_tools_to_model_edge(
@@ -1242,7 +1233,7 @@ async def amodel_node(state: AgentState, runtime: Runtime[ContextT]) -> dict[str
                 structured_output_tools=structured_output_tools,
                 end_destination=exit_node,
             ),
-            tools_to_model_destinations,
+            [loop_entry_node, exit_node],
         )
 
         # base destinations are tools and exit_node

libs/langchain_v1/tests/unit_tests/agents/__snapshots__/test_middleware_agent.ambr

@@ -20,6 +20,7 @@
   	__start__ --> NoopZero\2ebefore_agent;
   	model -.-> NoopTwo\2eafter_agent;
   	model -.-> tools;
+  	tools -.-> NoopTwo\2eafter_agent;
   	tools -.-> model;
   	NoopOne\2eafter_agent --> __end__;
   	classDef default fill:#f2f0ff,line-height:1.2
@@ -342,6 +343,7 @@
   	__start__ --> NoopSeven\2ebefore_model;
   	model --> NoopEight\2eafter_model;
   	tools -.-> NoopSeven\2ebefore_model;
+  	tools -.-> __end__;
   	classDef default fill:#f2f0ff,line-height:1.2
   	classDef first fill-opacity:0
   	classDef last fill:#bfb6fc
@@ -374,6 +376,7 @@
   	__start__ --> NoopSeven\2ebefore_model;
   	model --> NoopEight\2eafter_model;
   	tools -.-> NoopSeven\2ebefore_model;
+  	tools -.-> __end__;
   	classDef default fill:#f2f0ff,line-height:1.2
   	classDef first fill-opacity:0
   	classDef last fill:#bfb6fc
@@ -406,6 +409,7 @@
   	__start__ --> NoopSeven\2ebefore_model;
   	model --> NoopEight\2eafter_model;
   	tools -.-> NoopSeven\2ebefore_model;
+  	tools -.-> __end__;
   	classDef default fill:#f2f0ff,line-height:1.2
   	classDef first fill-opacity:0
   	classDef last fill:#bfb6fc
@@ -438,6 +442,7 @@
   	__start__ --> NoopSeven\2ebefore_model;
   	model --> NoopEight\2eafter_model;
   	tools -.-> NoopSeven\2ebefore_model;
+  	tools -.-> __end__;
   	classDef default fill:#f2f0ff,line-height:1.2
   	classDef first fill-opacity:0
   	classDef last fill:#bfb6fc
@@ -470,6 +475,7 @@
   	__start__ --> NoopSeven\2ebefore_model;
   	model --> NoopEight\2eafter_model;
   	tools -.-> NoopSeven\2ebefore_model;
+  	tools -.-> __end__;
   	classDef default fill:#f2f0ff,line-height:1.2
   	classDef first fill-opacity:0
   	classDef last fill:#bfb6fc
@@ -491,6 +497,7 @@
   	__start__ --> model;
   	model -.-> __end__;
   	model -.-> tools;
+  	tools -.-> __end__;
   	tools -.-> model;
   	classDef default fill:#f2f0ff,line-height:1.2
   	classDef first fill-opacity:0