From c63fcc96ead36780dae81cb37672ffd4610a5bb4 Mon Sep 17 00:00:00 2001
From: Jeremiah Lowin <153965+jlowin@users.noreply.github.com>
Date: Sun, 4 May 2025 12:18:28 -0400
Subject: [PATCH 1/2] Remove is_async attribute

---
 src/fastmcp/server/proxy.py      | 1 -
 tests/tools/test_tool.py         | 3 ---
 tests/tools/test_tool_manager.py | 3 ---
 3 files changed, 7 deletions(-)

diff --git a/src/fastmcp/server/proxy.py b/src/fastmcp/server/proxy.py
index 52e63bfa3..a2f83fa4c 100644
--- a/src/fastmcp/server/proxy.py
+++ b/src/fastmcp/server/proxy.py
@@ -52,7 +52,6 @@ class ProxyTool(Tool):
             description=tool.description,
             parameters=tool.inputSchema,
             fn=_proxy_passthrough,
-            is_async=True,
         )
 
     async def run(
diff --git a/tests/tools/test_tool.py b/tests/tools/test_tool.py
index e0316f81f..a12953e41 100644
--- a/tests/tools/test_tool.py
+++ b/tests/tools/test_tool.py
@@ -18,7 +18,6 @@ class TestToolFromFunction:
 
         assert tool.name == "add"
         assert tool.description == "Add two numbers."
-        assert tool.is_async is False
         assert tool.parameters["properties"]["a"]["type"] == "integer"
         assert tool.parameters["properties"]["b"]["type"] == "integer"
 
@@ -33,7 +32,6 @@ class TestToolFromFunction:
 
         assert tool.name == "fetch_data"
         assert tool.description == "Fetch data from URL."
-        assert tool.is_async is True
         assert tool.parameters["properties"]["url"]["type"] == "string"
 
     def test_pydantic_model_function(self):
@@ -51,7 +49,6 @@ class TestToolFromFunction:
 
         assert tool.name == "create_user"
         assert tool.description == "Create a new user."
-        assert tool.is_async is False
         assert "name" in tool.parameters["$defs"]["UserInput"]["properties"]
         assert "age" in tool.parameters["$defs"]["UserInput"]["properties"]
         assert "flag" in tool.parameters["properties"]
diff --git a/tests/tools/test_tool_manager.py b/tests/tools/test_tool_manager.py
index 0aaaca128..6cc44a36b 100644
--- a/tests/tools/test_tool_manager.py
+++ b/tests/tools/test_tool_manager.py
@@ -31,7 +31,6 @@ class TestAddTools:
         assert tool is not None
         assert tool.name == "add"
         assert tool.description == "Add two numbers."
-        assert tool.is_async is False
         assert tool.parameters["properties"]["a"]["type"] == "integer"
         assert tool.parameters["properties"]["b"]["type"] == "integer"
 
@@ -49,7 +48,6 @@ class TestAddTools:
         assert tool is not None
         assert tool.name == "fetch_data"
         assert tool.description == "Fetch data from URL."
-        assert tool.is_async is True
         assert tool.parameters["properties"]["url"]["type"] == "string"
 
     def test_pydantic_model_function(self):
@@ -70,7 +68,6 @@ class TestAddTools:
         assert tool is not None
         assert tool.name == "create_user"
         assert tool.description == "Create a new user."
-        assert tool.is_async is False
         assert "name" in tool.parameters["$defs"]["UserInput"]["properties"]
         assert "age" in tool.parameters["$defs"]["UserInput"]["properties"]
         assert "flag" in tool.parameters["properties"]

From cdc08081904105a975b3bd8c825bbfcbf330f687 Mon Sep 17 00:00:00 2001
From: Jeremiah Lowin <153965+jlowin@users.noreply.github.com>
Date: Sun, 4 May 2025 12:21:06 -0400
Subject: [PATCH 2/2] Finish removing

---
 src/fastmcp/server/openapi.py | 3 ---
 src/fastmcp/tools/tool.py     | 3 ---
 2 files changed, 6 deletions(-)

diff --git a/src/fastmcp/server/openapi.py b/src/fastmcp/server/openapi.py
index daeba1ea5..82a04307b 100644
--- a/src/fastmcp/server/openapi.py
+++ b/src/fastmcp/server/openapi.py
@@ -122,7 +122,6 @@ class OpenAPITool(Tool):
         name: str,
         description: str,
         parameters: dict[str, Any],
-        is_async: bool = True,
         tags: set[str] = set(),
         timeout: float | None = None,
         annotations: ToolAnnotations | None = None,
@@ -133,7 +132,6 @@ class OpenAPITool(Tool):
             description=description,
             parameters=parameters,
             fn=self._execute_request,  # We'll use an instance method instead of a global function
-            is_async=is_async,
             context_kwarg="context",  # Default context keyword argument
             tags=tags,
             annotations=annotations,
@@ -550,7 +548,6 @@ class FastMCPOpenAPI(FastMCP):
             name=tool_name,
             description=enhanced_description,
             parameters=combined_schema,
-            is_async=True,
             tags=set(route.tags or []),
             timeout=self._timeout,
         )
diff --git a/src/fastmcp/tools/tool.py b/src/fastmcp/tools/tool.py
index 492dbeaca..4f178a6e8 100644
--- a/src/fastmcp/tools/tool.py
+++ b/src/fastmcp/tools/tool.py
@@ -40,7 +40,6 @@ class Tool(BaseModel):
     name: str = Field(description="Name of the tool")
     description: str = Field(description="Description of what the tool does")
     parameters: dict[str, Any] = Field(description="JSON schema for tool parameters")
-    is_async: bool = Field(description="Whether the tool is async")
     context_kwarg: str | None = Field(
         None, description="Name of the kwarg that should receive context"
     )
@@ -74,7 +73,6 @@ class Tool(BaseModel):
             raise ValueError("You must provide a name for lambda functions")
 
         func_doc = description or fn.__doc__ or ""
-        is_async = inspect.iscoroutinefunction(fn)
 
         if inspect.ismethod(fn) and hasattr(fn, "__func__"):
             sig = inspect.signature(fn.__func__)
@@ -96,7 +94,6 @@ class Tool(BaseModel):
             name=func_name,
             description=func_doc,
             parameters=schema,
-            is_async=is_async,
             context_kwarg=context_kwarg,
             tags=tags or set(),
             annotations=annotations,