From 7fb81863b0cfccd33933843be78d8676514d92c2 Mon Sep 17 00:00:00 2001
From: Eugene Yurtsev <eyurtsev@gmail.com>
Date: Thu, 16 Oct 2025 17:15:06 -0400
Subject: [PATCH] Revert "fix(langchain): conditional edge from tools to end
 (#33520)"

This reverts commit e10d99b72801fe84e33f2b3ab2ef9dc4fbf2c483.
---
 libs/langchain_v1/langchain/agents/factory.py | 11 +--
 .../__snapshots__/test_middleware_agent.ambr  |  7 ++
 .../test_return_direct_graph.ambr             | 69 ------------------
 .../agents/test_return_direct_graph.py        | 73 -------------------
 4 files changed, 8 insertions(+), 152 deletions(-)
 delete mode 100644 libs/langchain_v1/tests/unit_tests/agents/__snapshots__/test_return_direct_graph.ambr
 delete mode 100644 libs/langchain_v1/tests/unit_tests/agents/test_return_direct_graph.py

diff --git a/libs/langchain_v1/langchain/agents/factory.py b/libs/langchain_v1/langchain/agents/factory.py
index 3af577d0a42f0..5c0d34529e795 100644
--- a/libs/langchain_v1/langchain/agents/factory.py
+++ b/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
diff --git a/libs/langchain_v1/tests/unit_tests/agents/__snapshots__/test_middleware_agent.ambr b/libs/langchain_v1/tests/unit_tests/agents/__snapshots__/test_middleware_agent.ambr
index 75be381108bcf..6f1e17badccbe 100644
--- a/libs/langchain_v1/tests/unit_tests/agents/__snapshots__/test_middleware_agent.ambr
+++ b/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
diff --git a/libs/langchain_v1/tests/unit_tests/agents/__snapshots__/test_return_direct_graph.ambr b/libs/langchain_v1/tests/unit_tests/agents/__snapshots__/test_return_direct_graph.ambr
deleted file mode 100644
index f3e223f8df6b2..0000000000000
--- a/libs/langchain_v1/tests/unit_tests/agents/__snapshots__/test_return_direct_graph.ambr
+++ /dev/null
@@ -1,69 +0,0 @@
-# serializer version: 1
-# name: test_agent_graph_with_mixed_tools
-  '''
-  ---
-  config:
-    flowchart:
-      curve: linear
-  ---
-  graph TD;
-  	__start__([<p>__start__</p>]):::first
-  	model(model)
-  	tools(tools)
-  	__end__([<p>__end__</p>]):::last
-  	__start__ --> model;
-  	model -.-> __end__;
-  	model -.-> tools;
-  	tools -.-> __end__;
-  	tools -.-> model;
-  	classDef default fill:#f2f0ff,line-height:1.2
-  	classDef first fill-opacity:0
-  	classDef last fill:#bfb6fc
-  
-  '''
-# ---
-# name: test_agent_graph_with_return_direct_tool
-  '''
-  ---
-  config:
-    flowchart:
-      curve: linear
-  ---
-  graph TD;
-  	__start__([<p>__start__</p>]):::first
-  	model(model)
-  	tools(tools)
-  	__end__([<p>__end__</p>]):::last
-  	__start__ --> model;
-  	model -.-> __end__;
-  	model -.-> tools;
-  	tools -.-> __end__;
-  	tools -.-> model;
-  	classDef default fill:#f2f0ff,line-height:1.2
-  	classDef first fill-opacity:0
-  	classDef last fill:#bfb6fc
-  
-  '''
-# ---
-# name: test_agent_graph_without_return_direct_tools
-  '''
-  ---
-  config:
-    flowchart:
-      curve: linear
-  ---
-  graph TD;
-  	__start__([<p>__start__</p>]):::first
-  	model(model)
-  	tools(tools)
-  	__end__([<p>__end__</p>]):::last
-  	__start__ --> model;
-  	model -.-> __end__;
-  	model -.-> tools;
-  	tools -.-> model;
-  	classDef default fill:#f2f0ff,line-height:1.2
-  	classDef first fill-opacity:0
-  	classDef last fill:#bfb6fc
-  
-  '''
-# ---
diff --git a/libs/langchain_v1/tests/unit_tests/agents/test_return_direct_graph.py b/libs/langchain_v1/tests/unit_tests/agents/test_return_direct_graph.py
deleted file mode 100644
index 6907aa01a8c03..0000000000000
--- a/libs/langchain_v1/tests/unit_tests/agents/test_return_direct_graph.py
+++ /dev/null
@@ -1,73 +0,0 @@
-"""Tests for return_direct tool graph structure."""
-
-from langchain_core.tools import tool
-from syrupy.assertion import SnapshotAssertion
-
-from langchain.agents.factory import create_agent
-
-from .model import FakeToolCallingModel
-
-
-def test_agent_graph_without_return_direct_tools(snapshot: SnapshotAssertion) -> None:
-    """Test that graph WITHOUT return_direct tools does NOT have edge from tools to end."""
-
-    @tool
-    def normal_tool(input_string: str) -> str:
-        """A normal tool without return_direct."""
-        return input_string
-
-    agent = create_agent(
-        model=FakeToolCallingModel(),
-        tools=[normal_tool],
-        system_prompt="You are a helpful assistant.",
-    )
-
-    # The mermaid diagram should NOT include an edge from tools to __end__
-    # when no tools have return_direct=True
-    mermaid_diagram = agent.get_graph().draw_mermaid()
-    assert mermaid_diagram == snapshot
-
-
-def test_agent_graph_with_return_direct_tool(snapshot: SnapshotAssertion) -> None:
-    """Test that graph WITH return_direct tools has correct edge from tools to end."""
-
-    @tool(return_direct=True)
-    def return_direct_tool(input_string: str) -> str:
-        """A tool with return_direct=True."""
-        return input_string
-
-    agent = create_agent(
-        model=FakeToolCallingModel(),
-        tools=[return_direct_tool],
-        system_prompt="You are a helpful assistant.",
-    )
-
-    # The mermaid diagram SHOULD include an edge from tools to __end__
-    # when at least one tool has return_direct=True
-    mermaid_diagram = agent.get_graph().draw_mermaid()
-    assert mermaid_diagram == snapshot
-
-
-def test_agent_graph_with_mixed_tools(snapshot: SnapshotAssertion) -> None:
-    """Test that graph with mixed tools (some return_direct, some not) has correct edges."""
-
-    @tool(return_direct=True)
-    def return_direct_tool(input_string: str) -> str:
-        """A tool with return_direct=True."""
-        return input_string
-
-    @tool
-    def normal_tool(input_string: str) -> str:
-        """A normal tool without return_direct."""
-        return input_string
-
-    agent = create_agent(
-        model=FakeToolCallingModel(),
-        tools=[return_direct_tool, normal_tool],
-        system_prompt="You are a helpful assistant.",
-    )
-
-    # The mermaid diagram SHOULD include an edge from tools to __end__
-    # because at least one tool has return_direct=True
-    mermaid_diagram = agent.get_graph().draw_mermaid()
-    assert mermaid_diagram == snapshot