[DNM] Support functools.partial as tools, prompts, and resources

src/fastmcp/apps/app.py

@@ -27,7 +27,6 @@ def save_contact(name: str, email: str) -> str:
 
 from __future__ import annotations
 
-import inspect
 from collections.abc import AsyncIterator, Callable, Sequence
 from contextlib import asynccontextmanager, suppress
 from typing import Any, Literal, TypeVar, overload
@@ -38,6 +37,7 @@ def save_contact(name: str, email: str) -> str:
 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__)
@@ -100,7 +100,7 @@ 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):

src/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

src/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 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, PromptError
 from fastmcp.prompts.base import Prompt, PromptArgument, PromptResult
 from fastmcp.server.auth.authorization import AuthCheck
@@ -36,6 +35,11 @@
     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.json_schema import compress_schema
 from fastmcp.utilities.logging import get_logger
 from fastmcp.utilities.types import get_cached_typeadapter
@@ -137,9 +141,7 @@ def from_function(
                 auth=auth,
             )
 
-        func_name = (
-            metadata.name or getattr(fn, "__name__", None) or fn.__class__.__name__
-        )
+        func_name = metadata.name or get_callable_name(fn)
 
         if func_name == "<lambda>":
             raise ValueError("You must provide a name for lambda functions")
@@ -158,22 +160,10 @@ def from_function(
             else inspect.getdoc(fn)
         )
 
-        # Normalize task to TaskConfig and validate
-        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 = TaskConfig.normalize(metadata.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
-        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__
+        fn = prepare_callable(fn)
 
         # Transform Context type annotations to Depends() for unified DI
         fn = transform_context_annotations(fn)
@@ -452,8 +442,7 @@ def attach_metadata(fn: F, prompt_name: str | None) -> F:
             task=task,
             auth=auth,
         )
-        target = fn.__func__ if hasattr(fn, "__func__") else fn
-        target.__fastmcp__ = metadata
+        set_fastmcp_meta(fn, metadata)
         return fn
 
     def decorator(fn: F, prompt_name: str | None) -> F:
@@ -467,7 +456,7 @@ def decorator(fn: F, prompt_name: str | None) -> F:
             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:

src/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.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 @@
     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 @@ def from_function(
 
         uri_obj = AnyUrl(metadata.uri)
 
-        # Get function name - use class name for callable objects
-        func_name = (
-            metadata.name or getattr(fn, "__name__", None) or fn.__class__.__name__
-        )
+        func_name = metadata.name or get_callable_name(fn)
 
-        # Normalize task to TaskConfig and validate
-        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 = TaskConfig.normalize(metadata.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
-        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__
+        fn = prepare_callable(fn)
 
         # 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 attach_metadata(fn: F) -> F:
             task=task,
             auth=auth,
         )
-        target = fn.__func__ if hasattr(fn, "__func__") else fn
-        target.__fastmcp__ = metadata
+        set_fastmcp_meta(fn, metadata)
         return fn
 
     def decorator(fn: F) -> F:

src/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 @@
     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
@@ -488,7 +488,7 @@ def from_function(
     ) -> 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")
 
@@ -555,21 +555,10 @@ def from_function(
 
         description = description if description is not None else inspect.getdoc(fn)
 
-        # Normalize task to TaskConfig and validate
-        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 = TaskConfig.normalize(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
-        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__
+        fn = prepare_callable(fn)
 
         # Transform Context type annotations to Depends() for unified DI
         fn = transform_context_annotations(fn)

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

@@ -15,10 +15,12 @@
 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 @@ def decorate_and_register(
                     auth=auth,
                     enabled=enabled,
                 )
-                target = fn.__func__ if hasattr(fn, "__func__") else fn
-                target.__fastmcp__ = metadata  # type: ignore[attr-defined]  # ty:ignore[unresolved-attribute]
+                set_fastmcp_meta(fn, metadata)
                 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):

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

@@ -14,11 +14,13 @@
 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 @@ def get_weather(city: str) -> str:
         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 @@ def decorator(fn: AnyFunction) -> Any:
                     auth=auth,
                     enabled=enabled,
                 )
-                target = fn.__func__ if hasattr(fn, "__func__") else fn
-                target.__fastmcp__ = metadata  # type: ignore[attr-defined]  # ty:ignore[unresolved-attribute]
+                set_fastmcp_meta(fn, metadata)
                 self.add_resource(fn)
                 return fn
 

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

@@ -27,11 +27,13 @@
 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:
@@ -396,12 +398,11 @@ def decorate_and_register(
                     auth=auth,
                     enabled=enabled,
                 )
-                target = fn.__func__ if hasattr(fn, "__func__") else fn
-                target.__fastmcp__ = metadata  # type: ignore[attr-defined]  # ty:ignore[unresolved-attribute]
+                set_fastmcp_meta(fn, metadata)
                 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):

src/fastmcp/server/tasks/config.py

@@ -6,14 +6,13 @@
 
 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 @@ def from_bool(cls, value: bool) -> 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 @@ def validate_function(self, fn: Callable[..., Any], name: str) -> None:
         require_docket(f"`task=True` on function '{name}'")
 
         # Unwrap callable classes and staticmethods
-        fn_to_check = 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__
+        fn_to_check = prepare_callable(fn)
 
         if not is_coroutine_function(fn_to_check):
             raise ValueError(