From 4b474a2646aba5935f82f6bbf0ac2dd386bebfa9 Mon Sep 17 00:00:00 2001
From: Jack Yuan <jackypc@amazon.com>
Date: Fri, 29 Aug 2025 15:40:43 -0400
Subject: [PATCH 1/2] fix: fix loading tools with same tool name

---
 src/strands/tools/registry.py        |  8 +++++++
 tests/strands/tools/test_registry.py | 36 ++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+)

diff --git a/src/strands/tools/registry.py b/src/strands/tools/registry.py
index fd395ae77..23d03bb70 100644
--- a/src/strands/tools/registry.py
+++ b/src/strands/tools/registry.py
@@ -190,6 +190,14 @@ def register_tool(self, tool: AgentTool) -> None:
             tool.is_dynamic,
         )
 
+        # Check duplicate tool name, throw on duplicate tool names except if hot_reloading is enabled
+        if tool.tool_name in self.registry:
+            if not tool.supports_hot_reload:
+                raise ValueError(
+                    f"Tool name '{tool.tool_name}' already exists. Cannot register tools with exact same name."
+                )
+
+        # Check for normalized name conflicts (- vs _)
         if self.registry.get(tool.tool_name) is None:
             normalized_name = tool.tool_name.replace("-", "_")
 
diff --git a/tests/strands/tools/test_registry.py b/tests/strands/tools/test_registry.py
index 66494c987..ca3cded4c 100644
--- a/tests/strands/tools/test_registry.py
+++ b/tests/strands/tools/test_registry.py
@@ -120,3 +120,39 @@ def function() -> str:
         "tool_f",
     ]
     assert tru_tool_names == exp_tool_names
+
+
+def test_register_tool_duplicate_name_without_hot_reload():
+    """Test that registering a tool with duplicate name raises ValueError when hot reload is not supported."""
+    tool_1 = PythonAgentTool(tool_name="duplicate_tool", tool_spec=MagicMock(), tool_func=lambda: None)
+    tool_2 = PythonAgentTool(tool_name="duplicate_tool", tool_spec=MagicMock(), tool_func=lambda: None)
+
+    tool_registry = ToolRegistry()
+    tool_registry.register_tool(tool_1)
+
+    with pytest.raises(
+        ValueError, match="Tool name 'duplicate_tool' already exists. Cannot register tools with exact same name."
+    ):
+        tool_registry.register_tool(tool_2)
+
+
+def test_register_tool_duplicate_name_with_hot_reload():
+    """Test that registering a tool with duplicate name succeeds when hot reload is supported."""
+    # Create mock tools with hot reload support
+    tool_1 = MagicMock(spec=PythonAgentTool)
+    tool_1.tool_name = "hot_reload_tool"
+    tool_1.supports_hot_reload = True
+    tool_1.is_dynamic = False
+
+    tool_2 = MagicMock(spec=PythonAgentTool)
+    tool_2.tool_name = "hot_reload_tool"
+    tool_2.supports_hot_reload = True
+    tool_2.is_dynamic = False
+
+    tool_registry = ToolRegistry()
+    tool_registry.register_tool(tool_1)
+
+    tool_registry.register_tool(tool_2)
+
+    # Verify the second tool replaced the first
+    assert tool_registry.registry["hot_reload_tool"] == tool_2

From 2ddefa2a2d68e4bfaa1f37e987072c8fc5c6fb46 Mon Sep 17 00:00:00 2001
From: Jack Yuan <jackypc@amazon.com>
Date: Fri, 29 Aug 2025 16:15:52 -0400
Subject: [PATCH 2/2] simplify if condition

---
 src/strands/tools/registry.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/strands/tools/registry.py b/src/strands/tools/registry.py
index 23d03bb70..6bb76f560 100644
--- a/src/strands/tools/registry.py
+++ b/src/strands/tools/registry.py
@@ -191,8 +191,7 @@ def register_tool(self, tool: AgentTool) -> None:
         )
 
         # Check duplicate tool name, throw on duplicate tool names except if hot_reloading is enabled
-        if tool.tool_name in self.registry:
-            if not tool.supports_hot_reload:
+        if tool.tool_name in self.registry and not tool.supports_hot_reload:
                 raise ValueError(
                     f"Tool name '{tool.tool_name}' already exists. Cannot register tools with exact same name."
                 )