refactor: clean up visualization functions by removing unused nodes and improving type hints

src/agents/extensions/visualization.py

@@ -1,3 +1,5 @@
+from typing import Optional
+
 import graphviz
 
 from agents import Agent
@@ -20,8 +22,6 @@ def get_main_graph(agent: Agent) -> str:
         graph [splines=true];
         node [fontname="Arial"];
         edge [penwidth=1.5];
-        "__start__" [shape=ellipse, style=filled, fillcolor=lightblue];
-        "__end__" [shape=ellipse, style=filled, fillcolor=lightblue];
     """
     ]
     parts.append(get_all_nodes(agent))
@@ -30,8 +30,6 @@ def get_main_graph(agent: Agent) -> str:
     return "".join(parts)
 
 
-from typing import Optional
-
 def get_all_nodes(agent: Agent, parent: Optional[Agent] = None) -> str:
     """
     Recursively generates the nodes for the given agent and its handoffs in DOT format.
@@ -59,12 +57,14 @@ def get_all_nodes(agent: Agent, parent: Optional[Agent] = None) -> str:
     for handoff in agent.handoffs:
         if isinstance(handoff, Handoff):
             parts.append(
-                f'"{handoff.agent_name}" [label="{handoff.agent_name}", shape=box, style=filled, style=rounded, '
+                f'"{handoff.agent_name}" [label="{handoff.agent_name}", shape=box, '
+                f"shape=box, style=filled, style=rounded, "
                 f"fillcolor=lightyellow, width=1.5, height=0.8];"
             )
         if isinstance(handoff, Agent):
             parts.append(
-                f'"{handoff.name}" [label="{handoff.name}", shape=box, style=filled, style=rounded, '
+                f'"{handoff.name}" [label="{handoff.name}", '
+                f"shape=box, style=filled, style=rounded, "
                 f"fillcolor=lightyellow, width=1.5, height=0.8];"
             )
             parts.append(get_all_nodes(handoff))
@@ -85,19 +85,11 @@ def get_all_edges(agent: Agent, parent: Optional[Agent] = None) -> str:
     """
     parts = []
 
-    if not parent:
-        parts.append(f"""
-        "__start__" -> "{agent.name}";""")
-
     for tool in agent.tools:
         parts.append(f"""
         "{agent.name}" -> "{tool.name}" [style=dotted, penwidth=1.5];
         "{tool.name}" -> "{agent.name}" [style=dotted, penwidth=1.5];""")
 
-    if not agent.handoffs:
-        parts.append(f"""
-        "{agent.name}" -> "__end__";""")
-
     for handoff in agent.handoffs:
         if isinstance(handoff, Handoff):
             parts.append(f"""
@@ -110,8 +102,6 @@ def get_all_edges(agent: Agent, parent: Optional[Agent] = None) -> str:
     return "".join(parts)
 
 
-from typing import Optional
-
 def draw_graph(agent: Agent, filename: Optional[str] = None) -> graphviz.Source:
     """
     Draws the graph for the given agent and optionally saves it as a PNG file.

tests/test_visualization.py

@@ -10,6 +10,7 @@ from agents.extensions.visualization import (
     get_all_nodes,
     get_main_graph,
 )
+from agents.handoffs import Handoff
 
 
 @pytest.fixture
@@ -19,10 +20,8 @@ def mock_agent():
     tool2 = Mock()
     tool2.name = "Tool2"
 
-    handoff1 = Mock()
+    handoff1 = Mock(spec=Handoff)
-    handoff1.name = "Handoff1"
+    handoff1.agent_name = "Handoff1"
-    handoff1.tools = []
-    handoff1.handoffs = []
 
     agent = Mock(spec=Agent)
     agent.name = "Agent1"
@@ -34,12 +33,11 @@ def mock_agent():
 
 def test_get_main_graph(mock_agent):
     result = get_main_graph(mock_agent)
+    print(result)
     assert "digraph G" in result
     assert "graph [splines=true];" in result
     assert 'node [fontname="Arial"];' in result
     assert "edge [penwidth=1.5];" in result
-    assert '"__start__" [shape=ellipse, style=filled, fillcolor=lightblue];' in result
-    assert '"__end__" [shape=ellipse, style=filled, fillcolor=lightblue];' in result
     assert (
         '"Agent1" [label="Agent1", shape=box, style=filled, '
         "fillcolor=lightyellow, width=1.5, height=0.8];" in result
@@ -80,13 +78,11 @@ def test_get_all_nodes(mock_agent):
 
 def test_get_all_edges(mock_agent):
     result = get_all_edges(mock_agent)
-    assert '"__start__" -> "Agent1";' in result
     assert '"Agent1" -> "Tool1" [style=dotted, penwidth=1.5];' in result
     assert '"Tool1" -> "Agent1" [style=dotted, penwidth=1.5];' in result
     assert '"Agent1" -> "Tool2" [style=dotted, penwidth=1.5];' in result
     assert '"Tool2" -> "Agent1" [style=dotted, penwidth=1.5];' in result
     assert '"Agent1" -> "Handoff1";' in result
-    assert '"Handoff1" -> "__end__";' in result
 
 
 def test_draw_graph(mock_agent):
@@ -96,8 +92,6 @@ def test_draw_graph(mock_agent):
     assert "graph [splines=true];" in graph.source
     assert 'node [fontname="Arial"];' in graph.source
     assert "edge [penwidth=1.5];" in graph.source
-    assert '"__start__" [shape=ellipse, style=filled, fillcolor=lightblue];' in graph.source
-    assert '"__end__" [shape=ellipse, style=filled, fillcolor=lightblue];' in graph.source
     assert (
         '"Agent1" [label="Agent1", shape=box, style=filled, '
         "fillcolor=lightyellow, width=1.5, height=0.8];" in graph.source