Fix ruff SIM105: use contextlib.suppress

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

fastmcp_slim/fastmcp/apps/app.py

@@ -27,7 +27,6 @@ Usage::
 
 from __future__ import annotations
 
-import inspect
 from collections.abc import AsyncIterator, Callable, Sequence
 from contextlib import asynccontextmanager
 from typing import Any, Literal, TypeVar, overload
@@ -38,6 +37,7 @@ from fastmcp.server.auth.authorization import AuthCheck
 from fastmcp.server.providers.base import Provider
 from fastmcp.server.providers.local_provider import LocalProvider
 from fastmcp.tools.base import Tool
+from fastmcp.utilities.callable_utils import is_callable_object
 from fastmcp.utilities.logging import get_logger
 
 logger = get_logger(__name__)
@@ -111,7 +111,7 @@ def _dispatch_decorator(
     decorator_name: str,
 ) -> Any:
     """Shared dispatch logic for @app.tool() and @app.ui() calling patterns."""
-    if inspect.isroutine(name_or_fn):
+    if is_callable_object(name_or_fn):
         return register(name_or_fn, name)
 
     if isinstance(name_or_fn, str):

fastmcp_slim/fastmcp/decorators.py

@@ -39,3 +39,13 @@ def get_fastmcp_meta(fn: Any) -> Any | None:
     except ValueError:
         pass
     return None
+
+
+def set_fastmcp_meta(fn: Any, metadata: Any) -> None:
+    """Attach FastMCP metadata to a function, handling bound methods.
+
+    For bound methods and staticmethods, the metadata is attached to the
+    underlying ``__func__`` so that ``get_fastmcp_meta`` can find it.
+    """
+    target = fn.__func__ if hasattr(fn, "__func__") else fn
+    target.__fastmcp__ = metadata

fastmcp_slim/fastmcp/prompts/function_prompt.py

@@ -2,7 +2,6 @@
 
 from __future__ import annotations
 
-import functools
 import inspect
 import json
 import warnings
@@ -23,7 +22,7 @@ from mcp.types import Icon
 from pydantic.json_schema import SkipJsonSchema
 
 import fastmcp
-from fastmcp.decorators import resolve_task_config
+from fastmcp.decorators import resolve_task_config, set_fastmcp_meta
 from fastmcp.exceptions import FastMCPDeprecationWarning, FastMCPError, PromptError
 from fastmcp.prompts.base import Prompt, PromptArgument, PromptResult
 from fastmcp.server.auth.authorization import AuthCheck
@@ -36,6 +35,11 @@ from fastmcp.utilities.async_utils import (
     call_sync_fn_in_threadpool,
     is_coroutine_function,
 )
+from fastmcp.utilities.callable_utils import (
+    get_callable_name,
+    is_callable_object,
+    prepare_callable,
+)
 from fastmcp.utilities.docstring_parsing import ParsedDocstring, parse_docstring
 from fastmcp.utilities.json_schema import compress_schema
 from fastmcp.utilities.logging import get_logger
@@ -138,9 +142,7 @@ class FunctionPrompt(Prompt):
                 auth=auth,
             )
 
-        func_name = (
+        func_name = metadata.name or get_callable_name(fn)
-            metadata.name or getattr(fn, "__name__", None) or fn.__class__.__name__
-        )
 
         if func_name == "<lambda>":
             raise ValueError("You must provide a name for lambda functions")
@@ -157,22 +159,10 @@ class FunctionPrompt(Prompt):
         # docstring as the prompt description for callable class instances.
         outer_docstring = parse_docstring(fn)
 
-        # Normalize task to TaskConfig and validate
+        task_config = TaskConfig.normalize(metadata.task)
-        task_value = metadata.task
-        if task_value is None:
-            task_config = TaskConfig(mode="forbidden")
-        elif isinstance(task_value, bool):
-            task_config = TaskConfig.from_bool(task_value)
-        else:
-            task_config = task_value
         task_config.validate_function(fn, func_name)
 
-        # if the fn is a callable class, we need to get the __call__ method from here out
+        fn = prepare_callable(fn)
-        if not inspect.isroutine(fn) and not isinstance(fn, functools.partial):
-            fn = fn.__call__
-        # if the fn is a staticmethod, we need to work with the underlying function
-        if isinstance(fn, staticmethod):
-            fn = fn.__func__
 
         # For callable classes, argument descriptions must come from
         # __call__'s docstring — where the exposed parameters are actually
@@ -483,8 +473,7 @@ def prompt(
             task=task,
             auth=auth,
         )
-        target = fn.__func__ if hasattr(fn, "__func__") else fn
+        set_fastmcp_meta(fn, metadata)
-        target.__fastmcp__ = metadata
         return fn
 
     def decorator(fn: F, prompt_name: str | None) -> F:
@@ -498,7 +487,7 @@ def prompt(
             return create_prompt(fn, prompt_name)  # type: ignore[return-value]  # ty:ignore[invalid-return-type]
         return attach_metadata(fn, prompt_name)
 
-    if inspect.isroutine(name_or_fn):
+    if is_callable_object(name_or_fn):
         return decorator(name_or_fn, name)
     elif isinstance(name_or_fn, str):
         if name is not None:

fastmcp_slim/fastmcp/resources/function_resource.py

@@ -2,7 +2,6 @@
 
 from __future__ import annotations
 
-import functools
 import inspect
 import warnings
 from collections.abc import Callable
@@ -14,7 +13,7 @@ from pydantic import AnyUrl
 from pydantic.json_schema import SkipJsonSchema
 
 import fastmcp
-from fastmcp.decorators import resolve_task_config
+from fastmcp.decorators import resolve_task_config, set_fastmcp_meta
 from fastmcp.exceptions import FastMCPDeprecationWarning
 from fastmcp.resources.base import Resource, ResourceResult
 from fastmcp.server.auth.authorization import AuthCheck
@@ -27,6 +26,11 @@ from fastmcp.utilities.async_utils import (
     call_sync_fn_in_threadpool,
     is_coroutine_function,
 )
+from fastmcp.utilities.callable_utils import (
+    get_callable_name,
+    is_callable_object,
+    prepare_callable,
+)
 from fastmcp.utilities.mime import resolve_ui_mime_type
 
 if TYPE_CHECKING:
@@ -159,27 +163,12 @@ class FunctionResource(Resource):
 
         uri_obj = AnyUrl(metadata.uri)
 
-        # Get function name - use class name for callable objects
+        func_name = metadata.name or get_callable_name(fn)
-        func_name = (
-            metadata.name or getattr(fn, "__name__", None) or fn.__class__.__name__
-        )
 
-        # Normalize task to TaskConfig and validate
+        task_config = TaskConfig.normalize(metadata.task)
-        task_value = metadata.task
-        if task_value is None:
-            task_config = TaskConfig(mode="forbidden")
-        elif isinstance(task_value, bool):
-            task_config = TaskConfig.from_bool(task_value)
-        else:
-            task_config = task_value
         task_config.validate_function(fn, func_name)
 
-        # if the fn is a callable class, we need to get the __call__ method from here out
+        fn = prepare_callable(fn)
-        if not inspect.isroutine(fn) and not isinstance(fn, functools.partial):
-            fn = fn.__call__
-        # if the fn is a staticmethod, we need to work with the underlying function
-        if isinstance(fn, staticmethod):
-            fn = fn.__func__
 
         # Transform Context type annotations to Depends() for unified DI
         fn = transform_context_annotations(fn)
@@ -259,7 +248,7 @@ def resource(
     if isinstance(annotations, dict):
         annotations = Annotations(**annotations)
 
-    if inspect.isroutine(uri):
+    if is_callable_object(uri):
         raise TypeError(
             "The @resource decorator requires a URI. "
             "Use @resource('uri') instead of @resource"
@@ -325,8 +314,7 @@ def resource(
             task=task,
             auth=auth,
         )
-        target = fn.__func__ if hasattr(fn, "__func__") else fn
+        set_fastmcp_meta(fn, metadata)
-        target.__fastmcp__ = metadata
         return fn
 
     def decorator(fn: F) -> F:

fastmcp_slim/fastmcp/resources/template.py

@@ -2,7 +2,6 @@
 
 from __future__ import annotations
 
-import functools
 import inspect
 import re
 from collections.abc import Callable
@@ -30,6 +29,7 @@ from fastmcp.server.dependencies import (
     without_injected_parameters,
 )
 from fastmcp.server.tasks.config import TaskConfig, TaskMeta
+from fastmcp.utilities.callable_utils import get_callable_name, prepare_callable
 from fastmcp.utilities.components import FastMCPComponent
 from fastmcp.utilities.json_schema import compress_schema
 from fastmcp.utilities.mime import resolve_ui_mime_type
@@ -539,7 +539,7 @@ class FunctionResourceTemplate(ResourceTemplate):
     ) -> FunctionResourceTemplate:
         """Create a template from a function."""
 
-        func_name = name or getattr(fn, "__name__", None) or fn.__class__.__name__
+        func_name = name or get_callable_name(fn)
         if func_name == "<lambda>":
             raise ValueError("You must provide a name for lambda functions")
 
@@ -625,21 +625,10 @@ class FunctionResourceTemplate(ResourceTemplate):
 
         description = description if description is not None else inspect.getdoc(fn)
 
-        # Normalize task to TaskConfig and validate
+        task_config = TaskConfig.normalize(task)
-        if task is None:
-            task_config = TaskConfig(mode="forbidden")
-        elif isinstance(task, bool):
-            task_config = TaskConfig.from_bool(task)
-        else:
-            task_config = task
         task_config.validate_function(fn, func_name)
 
-        # if the fn is a callable class, we need to get the __call__ method from here out
+        fn = prepare_callable(fn)
-        if not inspect.isroutine(fn) and not isinstance(fn, functools.partial):
-            fn = fn.__call__
-        # if the fn is a staticmethod, we need to work with the underlying function
-        if isinstance(fn, staticmethod):
-            fn = fn.__func__
 
         # Transform Context type annotations to Depends() for unified DI
         fn = transform_context_annotations(fn)

fastmcp_slim/fastmcp/server/providers/local_provider/decorators/prompts.py

@@ -15,10 +15,12 @@ import mcp.types
 from mcp.types import AnyFunction
 
 import fastmcp
+from fastmcp.decorators import set_fastmcp_meta
 from fastmcp.prompts.base import Prompt
 from fastmcp.prompts.function_prompt import FunctionPrompt
 from fastmcp.server.auth.authorization import AuthCheck
 from fastmcp.server.tasks.config import TaskConfig
+from fastmcp.utilities.callable_utils import is_callable_object
 
 if TYPE_CHECKING:
     from fastmcp.server.providers.local_provider import LocalProvider
@@ -223,12 +225,11 @@ class PromptDecoratorMixin:
                     auth=auth,
                     enabled=enabled,
                 )
-                target = fn.__func__ if hasattr(fn, "__func__") else fn
+                set_fastmcp_meta(fn, metadata)
-                target.__fastmcp__ = metadata  # type: ignore[attr-defined]  # ty:ignore[unresolved-attribute]
                 self.add_prompt(fn)
                 return fn
 
-        if inspect.isroutine(name_or_fn):
+        if is_callable_object(name_or_fn):
             return decorate_and_register(name_or_fn, name)
 
         elif isinstance(name_or_fn, str):

fastmcp_slim/fastmcp/server/providers/local_provider/decorators/resources.py

@@ -14,11 +14,13 @@ import mcp.types
 from mcp.types import Annotations, AnyFunction
 
 import fastmcp
+from fastmcp.decorators import set_fastmcp_meta
 from fastmcp.resources.base import Resource
 from fastmcp.resources.function_resource import resource as standalone_resource
 from fastmcp.resources.template import ResourceTemplate
 from fastmcp.server.auth.authorization import AuthCheck
 from fastmcp.server.tasks.config import TaskConfig
+from fastmcp.utilities.callable_utils import is_callable_object
 
 if TYPE_CHECKING:
     from fastmcp.server.providers.local_provider import LocalProvider
@@ -159,7 +161,7 @@ class ResourceDecoratorMixin:
         if isinstance(annotations, dict):
             annotations = Annotations(**annotations)
 
-        if inspect.isroutine(uri):
+        if is_callable_object(uri):
             raise TypeError(
                 "The @resource decorator was used incorrectly. "
                 "It requires a URI as the first argument. "
@@ -234,8 +236,7 @@ class ResourceDecoratorMixin:
                     auth=auth,
                     enabled=enabled,
                 )
-                target = fn.__func__ if hasattr(fn, "__func__") else fn
+                set_fastmcp_meta(fn, metadata)
-                target.__fastmcp__ = metadata  # type: ignore[attr-defined]  # ty:ignore[unresolved-attribute]
                 self.add_resource(fn)
                 return fn
 

fastmcp_slim/fastmcp/server/providers/local_provider/decorators/tools.py

@@ -27,11 +27,13 @@ import mcp.types
 from mcp.types import AnyFunction, ToolAnnotations
 
 import fastmcp
+from fastmcp.decorators import set_fastmcp_meta
 from fastmcp.exceptions import FastMCPDeprecationWarning
 from fastmcp.server.auth.authorization import AuthCheck
 from fastmcp.server.tasks.config import TaskConfig
 from fastmcp.tools.base import Tool
 from fastmcp.tools.function_tool import FunctionTool
+from fastmcp.utilities.callable_utils import is_callable_object
 from fastmcp.utilities.types import NotSet, NotSetT
 
 try:
@@ -377,12 +379,11 @@ class ToolDecoratorMixin:
                     enabled=enabled,
                     run_in_thread=run_in_thread,
                 )
-                target = fn.__func__ if hasattr(fn, "__func__") else fn
+                set_fastmcp_meta(fn, metadata)
-                target.__fastmcp__ = metadata  # type: ignore[attr-defined]  # ty:ignore[unresolved-attribute]
                 tool_obj = self.add_tool(fn)
                 return fn
 
-        if inspect.isroutine(name_or_fn):
+        if is_callable_object(name_or_fn):
             return decorate_and_register(name_or_fn, name)
 
         elif isinstance(name_or_fn, str):

fastmcp_slim/fastmcp/server/tasks/config.py

@@ -6,14 +6,13 @@ handle task-augmented execution as specified in SEP-1686.
 
 from __future__ import annotations
 
-import functools
-import inspect
 from collections.abc import Callable
 from dataclasses import dataclass
 from datetime import timedelta
 from typing import Any, Literal
 
 from fastmcp.utilities.async_utils import is_coroutine_function
+from fastmcp.utilities.callable_utils import prepare_callable
 
 # Task execution modes per SEP-1686 / MCP ToolExecution.taskSupport
 TaskMode = Literal["forbidden", "optional", "required"]
@@ -90,6 +89,23 @@ class TaskConfig:
         """
         return cls(mode="optional" if value else "forbidden")
 
+    @classmethod
+    def normalize(cls, task: bool | TaskConfig | None) -> TaskConfig:
+        """Convert a task parameter to a TaskConfig.
+
+        Args:
+            task: True/False for simple enable/disable, TaskConfig for full
+                control, or None for the default (forbidden).
+
+        Returns:
+            A TaskConfig instance.
+        """
+        if task is None:
+            return cls(mode="forbidden")
+        if isinstance(task, bool):
+            return cls.from_bool(task)
+        return task
+
     def supports_tasks(self) -> bool:
         """Check if this component supports task execution.
 
@@ -126,15 +142,7 @@ class TaskConfig:
         require_docket(f"`task=True` on function '{name}'")
 
         # Unwrap callable classes and staticmethods
-        fn_to_check = fn
+        fn_to_check = prepare_callable(fn)
-        if (
-            not inspect.isroutine(fn)
-            and not isinstance(fn, functools.partial)
-            and callable(fn)
-        ):
-            fn_to_check = fn.__call__
-        if isinstance(fn_to_check, staticmethod):
-            fn_to_check = fn_to_check.__func__
 
         if not is_coroutine_function(fn_to_check):
             raise ValueError(

fastmcp_slim/fastmcp/tools/function_parsing.py

@@ -2,7 +2,6 @@
 
 from __future__ import annotations
 
-import functools
 import inspect
 import types
 from collections.abc import Callable
@@ -18,6 +17,7 @@ from fastmcp.server.dependencies import (
     without_injected_parameters,
 )
 from fastmcp.tools.base import ToolResult
+from fastmcp.utilities.callable_utils import get_callable_name, prepare_callable
 from fastmcp.utilities.docstring_parsing import ParsedDocstring, parse_docstring
 from fastmcp.utilities.json_schema import compress_schema
 from fastmcp.utilities.logging import get_logger
@@ -164,15 +164,10 @@ class ParsedFunction:
                         )
 
         # collect name and description before we potentially modify the function
-        fn_name = getattr(fn, "__name__", None) or fn.__class__.__name__
+        fn_name = get_callable_name(fn)
         outer_docstring = parse_docstring(fn)
 
-        # if the fn is a callable class, we need to get the __call__ method from here out
+        fn = prepare_callable(fn)
-        if not inspect.isroutine(fn) and not isinstance(fn, functools.partial):
-            fn = fn.__call__
-        # if the fn is a staticmethod, we need to work with the underlying function
-        if isinstance(fn, staticmethod):
-            fn = fn.__func__
 
         # For callable classes, parameter descriptions must come from
         # __call__'s docstring — where the exposed parameters are actually

fastmcp_slim/fastmcp/tools/function_tool.py

@@ -24,7 +24,7 @@ from pydantic import Field
 from pydantic.json_schema import SkipJsonSchema
 
 import fastmcp
-from fastmcp.decorators import get_fastmcp_meta, resolve_task_config
+from fastmcp.decorators import get_fastmcp_meta, resolve_task_config, set_fastmcp_meta
 from fastmcp.exceptions import FastMCPDeprecationWarning
 from fastmcp.server.auth.authorization import AuthCheck
 from fastmcp.server.dependencies import without_injected_parameters
@@ -39,6 +39,7 @@ from fastmcp.utilities.async_utils import (
     call_sync_fn_in_threadpool,
     is_coroutine_function,
 )
+from fastmcp.utilities.callable_utils import is_callable_object
 from fastmcp.utilities.logging import get_logger
 from fastmcp.utilities.types import (
     NotSet,
@@ -237,14 +238,7 @@ class FunctionTool(Tool):
                 "accept worker-thread dispatch."
             )
 
-        # Normalize task to TaskConfig
+        task_config = TaskConfig.normalize(metadata.task)
-        task_value = metadata.task
-        if task_value is None:
-            task_config = TaskConfig(mode="forbidden")
-        elif isinstance(task_value, bool):
-            task_config = TaskConfig.from_bool(task_value)
-        else:
-            task_config = task_value
         task_config.validate_function(fn, func_name)
 
         # Handle output_schema
@@ -516,8 +510,7 @@ def tool(
             auth=auth,
             run_in_thread=run_in_thread,
         )
-        target = fn.__func__ if hasattr(fn, "__func__") else fn
+        set_fastmcp_meta(fn, metadata)
-        target.__fastmcp__ = metadata
         return fn
 
     def decorator(fn: F, tool_name: str | None) -> F:
@@ -531,7 +524,7 @@ def tool(
             return create_tool(fn, tool_name)  # type: ignore[return-value]  # ty:ignore[invalid-return-type]
         return attach_metadata(fn, tool_name)
 
-    if inspect.isroutine(name_or_fn):
+    if is_callable_object(name_or_fn):
         return decorator(name_or_fn, name)
     elif isinstance(name_or_fn, str):
         if name is not None:

fastmcp_slim/fastmcp/utilities/callable_utils.py

@@ -0,0 +1,92 @@
+"""Utilities for handling callables, including functools.partial objects.
+
+Provides centralized helpers for the shared steps in the tool/prompt/resource
+``from_function`` pipelines, avoiding duplicated ``isinstance`` checks, name
+extraction logic, and callable unwrapping across the codebase.
+"""
+
+from __future__ import annotations
+
+import contextlib
+import functools
+import inspect
+from collections.abc import Callable
+from typing import Any, TypeGuard
+
+
+def is_callable_object(obj: Any) -> TypeGuard[Callable[..., Any]]:
+    """Check if an object is a callable suitable for use as a tool, resource, or prompt.
+
+    Returns True for functions, methods, builtins, and functools.partial objects.
+    This is a broader check than ``inspect.isroutine`` which returns False for
+    functools.partial.
+    """
+    return inspect.isroutine(obj) or isinstance(obj, functools.partial)
+
+
+def get_callable_name(fn: Any) -> str:
+    """Extract a human-readable name from a callable.
+
+    Handles functions, callable classes, and functools.partial:
+
+    - Regular functions: returns ``fn.__name__`` (e.g. ``"add"``)
+    - Callable classes: returns the class name (e.g. ``"MyTool"``)
+    - Partial with ``update_wrapper``: returns the wrapped name (e.g. ``"add"``)
+    - Partial without ``update_wrapper``: returns the underlying function name
+      (e.g. ``"add"`` instead of ``"partial"``)
+    """
+    name = getattr(fn, "__name__", None)
+    if name is not None:
+        return name
+    # functools.partial without update_wrapper — use the underlying function's name
+    if isinstance(fn, functools.partial):
+        return getattr(fn.func, "__name__", None) or fn.__class__.__name__
+    return fn.__class__.__name__
+
+
+def prepare_callable(fn: Callable[..., Any]) -> Callable[..., Any]:
+    """Prepare a callable for introspection by ``inspect.signature()`` and Pydantic.
+
+    This handles three cases that would otherwise require special-casing in every
+    ``from_function`` method:
+
+    1. **functools.partial with __wrapped__**: ``functools.update_wrapper`` sets
+       ``__wrapped__`` which causes ``inspect.signature()`` and Pydantic to follow
+       it back to the original function, ignoring the partial's bound arguments.
+       We strip ``__wrapped__`` by reconstructing the partial.
+
+    2. **Callable classes**: Non-routine callables (classes with ``__call__``) need
+       to be unwrapped to their ``__call__`` method so ``inspect.signature()`` sees
+       the right parameters.
+
+    3. **staticmethod**: Needs unwrapping to the underlying function.
+
+    Call this AFTER extracting name/doc from the original callable, since this
+    may change what ``__name__`` and ``__doc__`` return.
+    """
+    # Strip __wrapped__ from partials so Pydantic sees the partial's own
+    # signature with bound args removed, not the original function's signature.
+    if isinstance(fn, functools.partial) and hasattr(fn, "__wrapped__"):
+        old = fn
+        fn = functools.partial(fn.func, *fn.args, **fn.keywords)
+        # Preserve annotation metadata copied by functools.update_wrapper
+        # (e.g. __module__, __qualname__) needed for deferred annotation
+        # resolution when `from __future__ import annotations` is active.
+        for attr in functools.WRAPPER_ASSIGNMENTS:
+            try:
+                val = getattr(old, attr)
+            except AttributeError:
+                pass
+            else:
+                with contextlib.suppress(AttributeError):
+                    setattr(fn, attr, val)
+
+    # Callable classes (not routines, not partials) → unwrap to __call__
+    if not inspect.isroutine(fn) and not isinstance(fn, functools.partial):
+        fn = fn.__call__
+
+    # staticmethod → unwrap to underlying function
+    if isinstance(fn, staticmethod):
+        fn = fn.__func__
+
+    return fn

tests/tools/tool/test_partial.py

@@ -0,0 +1,129 @@
+"""Tests for functools.partial support as tools, prompts, and resources.
+
+See https://github.com/PrefectHQ/fastmcp/issues/3266
+"""
+
+import functools
+
+from mcp.types import TextContent
+
+from fastmcp import Client, FastMCP
+from fastmcp.tools.function_tool import FunctionTool as Tool
+
+
+class TestPartialTool:
+    """Test tools created from functools.partial objects."""
+
+    async def test_partial_sync(self):
+        def add(x: int, y: int) -> int:
+            return x + y
+
+        partial_add = functools.partial(add, y=10)
+        functools.update_wrapper(partial_add, add)
+
+        tool = Tool.from_function(partial_add)
+        result = await tool.run({"x": 5})
+        assert result.content == [TextContent(type="text", text="15")]
+
+    async def test_partial_async(self):
+        async def multiply(x: int, factor: int) -> int:
+            return x * factor
+
+        partial_mul = functools.partial(multiply, factor=3)
+        functools.update_wrapper(partial_mul, multiply)
+
+        tool = Tool.from_function(partial_mul)
+        result = await tool.run({"x": 7})
+        assert result.content == [TextContent(type="text", text="21")]
+
+    async def test_partial_preserves_name(self):
+        def greet(name: str, greeting: str = "Hello") -> str:
+            """Greet someone."""
+            return f"{greeting}, {name}!"
+
+        partial_greet = functools.partial(greet, greeting="Hi")
+        functools.update_wrapper(partial_greet, greet)
+
+        tool = Tool.from_function(partial_greet)
+        assert tool.name == "greet"
+        assert tool.description == "Greet someone."
+
+    async def test_partial_without_update_wrapper(self):
+        def add(x: int, y: int) -> int:
+            return x + y
+
+        partial_add = functools.partial(add, y=10)
+
+        tool = Tool.from_function(partial_add, name="add_ten")
+        result = await tool.run({"x": 5})
+        assert result.content == [TextContent(type="text", text="15")]
+
+    async def test_partial_with_add_tool(self):
+        mcp = FastMCP("test")
+
+        def greet(name: str, greeting: str = "Hello") -> str:
+            return f"{greeting}, {name}!"
+
+        partial_greet = functools.partial(greet, greeting="Hey")
+        functools.update_wrapper(partial_greet, greet)
+
+        mcp.add_tool(partial_greet)
+
+        result = await mcp.call_tool("greet", {"name": "World"})
+        assert result.content == [TextContent(type="text", text="Hey, World!")]
+
+    async def test_partial_with_server_tool_decorator(self):
+        mcp = FastMCP("test")
+
+        def add(x: int, y: int) -> int:
+            return x + y
+
+        partial_add = functools.partial(add, y=100)
+        functools.update_wrapper(partial_add, add)
+
+        mcp.tool(partial_add)
+
+        result = await mcp.call_tool("add", {"x": 5})
+        assert result.content == [TextContent(type="text", text="105")]
+
+
+class TestPartialPrompt:
+    """Test prompts created from functools.partial objects."""
+
+    async def test_partial_prompt_with_decorator(self):
+        """Partial can be registered via @mcp.prompt() decorator."""
+        mcp = FastMCP("test")
+
+        def greet_prompt(name: str, lang: str) -> str:
+            return f"Say hello to {name} in {lang}."
+
+        partial_greet = functools.partial(greet_prompt, lang="French")
+        functools.update_wrapper(partial_greet, greet_prompt)
+
+        mcp.prompt(partial_greet)
+
+        async with Client(mcp) as client:
+            result = await client.get_prompt("greet_prompt", {"name": "Alice"})
+            assert "Alice" in str(result.messages[0])
+            assert "French" in str(result.messages[0])
+
+
+class TestPartialResource:
+    """Test resources created from functools.partial objects."""
+
+    async def test_partial_resource_with_decorator(self):
+        """Partial can be registered via @mcp.resource() decorator."""
+        mcp = FastMCP("test")
+
+        def get_data(key: str, fmt: str = "text") -> str:
+            return f"{key} in {fmt} format"
+
+        partial_data = functools.partial(get_data, fmt="json")
+        functools.update_wrapper(partial_data, get_data)
+
+        mcp.resource("data://{key}")(partial_data)
+
+        async with Client(mcp) as client:
+            content = await client.read_resource("data://users")
+            assert "users" in str(content)
+            assert "json" in str(content)

tests/utilities/test_callable_utils.py

@@ -0,0 +1,121 @@
+"""Tests for callable utility functions."""
+
+import functools
+
+from fastmcp.utilities.callable_utils import (
+    get_callable_name,
+    is_callable_object,
+    prepare_callable,
+)
+
+
+class TestIsCallableObject:
+    def test_function(self):
+        def fn():
+            pass
+
+        assert is_callable_object(fn) is True
+
+    def test_async_function(self):
+        async def fn():
+            pass
+
+        assert is_callable_object(fn) is True
+
+    def test_partial(self):
+        def fn(x, y):
+            return x + y
+
+        assert is_callable_object(functools.partial(fn, y=1)) is True
+
+    def test_callable_class(self):
+        class MyCallable:
+            def __call__(self):
+                pass
+
+        assert is_callable_object(MyCallable()) is False
+
+    def test_string(self):
+        assert is_callable_object("not a callable") is False
+
+    def test_none(self):
+        assert is_callable_object(None) is False
+
+
+class TestGetCallableName:
+    def test_function(self):
+        def my_function():
+            pass
+
+        assert get_callable_name(my_function) == "my_function"
+
+    def test_lambda(self):
+        assert get_callable_name(lambda: None) == "<lambda>"
+
+    def test_partial_with_update_wrapper(self):
+        def add(x, y):
+            return x + y
+
+        p = functools.partial(add, y=10)
+        functools.update_wrapper(p, add)
+        assert get_callable_name(p) == "add"
+
+    def test_partial_without_update_wrapper(self):
+        def add(x, y):
+            return x + y
+
+        p = functools.partial(add, y=10)
+        assert get_callable_name(p) == "add"
+
+    def test_callable_class(self):
+        class MyTool:
+            def __call__(self):
+                pass
+
+        assert get_callable_name(MyTool()) == "MyTool"
+
+
+class TestPrepareCallable:
+    def test_regular_function_unchanged(self):
+        def fn(x):
+            return x
+
+        assert prepare_callable(fn) is fn
+
+    def test_strips_wrapped_from_partial(self):
+        def add(x, y):
+            return x + y
+
+        p = functools.partial(add, y=10)
+        functools.update_wrapper(p, add)
+        assert hasattr(p, "__wrapped__")
+
+        prepared = prepare_callable(p)
+        assert isinstance(prepared, functools.partial)
+        assert not hasattr(prepared, "__wrapped__")
+        assert prepared.keywords == {"y": 10}
+
+    def test_partial_without_wrapper_unchanged(self):
+        def add(x, y):
+            return x + y
+
+        p = functools.partial(add, y=10)
+        prepared = prepare_callable(p)
+        assert isinstance(prepared, functools.partial)
+        assert prepared.func is add
+
+    def test_callable_class_unwrapped(self):
+        class MyCallable:
+            def __call__(self, x):
+                return x
+
+        obj = MyCallable()
+        prepared = prepare_callable(obj)
+        assert prepared == obj.__call__
+
+    def test_staticmethod_unwrapped(self):
+        def fn(x):
+            return x
+
+        sm = staticmethod(fn)
+        assert prepare_callable(sm) is fn