From 1fa2e67403310ff504ac5fefa0c59eace81a27ab Mon Sep 17 00:00:00 2001
From: Jeremiah Lowin <153965+jlowin@users.noreply.github.com>
Date: Thu, 24 Apr 2025 12:11:12 -0400
Subject: [PATCH] Improve error message when parsing params

---
 src/fastmcp/tools/tool.py | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/fastmcp/tools/tool.py b/src/fastmcp/tools/tool.py
index cfdef7692..e4af4749a 100644
--- a/src/fastmcp/tools/tool.py
+++ b/src/fastmcp/tools/tool.py
@@ -76,7 +76,12 @@ class Tool(BaseModel):
             fn_callable,
             skip_names=[context_kwarg] if context_kwarg is not None else [],
         )
-        parameters = func_arg_metadata.arg_model.model_json_schema()
+        try:
+            parameters = func_arg_metadata.arg_model.model_json_schema()
+        except Exception as e:
+            raise TypeError(
+                f'Unable to parse parameters for function "{fn.__name__}": {e}'
+            ) from e
 
         return cls(
             fn=fn_callable,