From b8f3eb9d7f4c135dc7e72f6fefa809649df933bf Mon Sep 17 00:00:00 2001
From: Patrick Gray <pgrayy@amazon.com>
Date: Thu, 26 Jun 2025 12:18:52 +0000
Subject: [PATCH] tools - stop filter $defs

---
 src/strands/tools/decorator.py | 2 +-
 src/strands/tools/registry.py  | 4 ++++
 src/strands/tools/tools.py     | 5 +++++
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/strands/tools/decorator.py b/src/strands/tools/decorator.py
index 3d579c3a0..33aa3dd6d 100644
--- a/src/strands/tools/decorator.py
+++ b/src/strands/tools/decorator.py
@@ -195,7 +195,7 @@ def _clean_pydantic_schema(self, schema: Dict[str, Any]) -> None:
             schema: The Pydantic-generated JSON schema to clean up (modified in place).
         """
         # Remove Pydantic metadata
-        keys_to_remove = ["title", "$defs", "additionalProperties"]
+        keys_to_remove = ["title", "additionalProperties"]
         for key in keys_to_remove:
             if key in schema:
                 del schema[key]
diff --git a/src/strands/tools/registry.py b/src/strands/tools/registry.py
index acaf6e368..5e335ff2b 100644
--- a/src/strands/tools/registry.py
+++ b/src/strands/tools/registry.py
@@ -538,6 +538,10 @@ def validate_tool_spec(self, tool_spec: ToolSpec) -> None:
                 }
                 continue
 
+            # It is expected that type and description are already included in referenced $def.
+            if "$ref" in prop_def:
+                continue
+
             if "type" not in prop_def:
                 prop_def["type"] = "string"
             if "description" not in prop_def:
diff --git a/src/strands/tools/tools.py b/src/strands/tools/tools.py
index 8dde1d09e..9047ad57b 100644
--- a/src/strands/tools/tools.py
+++ b/src/strands/tools/tools.py
@@ -81,6 +81,11 @@ def _normalize_property(prop_name: str, prop_def: Any) -> Dict[str, Any]:
 
     # Copy existing property, ensuring defaults
     normalized_prop = prop_def.copy()
+
+    # It is expected that type and description are already included in referenced $def.
+    if "$ref" in normalized_prop:
+        return normalized_prop
+
     normalized_prop.setdefault("type", "string")
     normalized_prop.setdefault("description", f"Property {prop_name}")
     return normalized_prop