Set generics without bounds to default=Any

This change addresses strict type checker warnings by adding default=Any
to TypeVar definitions that lack bounds. Uses typing_extensions.TypeVar
for compatibility with Python 3.10+.

Co-authored-by: William Easton <strawgate@users.noreply.github.com>

src/fastmcp/client/elicitation.py

@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 from collections.abc import Awaitable, Callable
-from typing import Any, Generic, TypeAlias, TypeVar
+from typing import Any, Generic, TypeAlias
 
 import mcp.types
 from mcp import ClientSession
@@ -10,12 +10,13 @@ from mcp.shared.context import LifespanContextT, RequestContext
 from mcp.types import ElicitRequestParams
 from mcp.types import ElicitResult as MCPElicitResult
 from pydantic_core import to_jsonable_python
+from typing_extensions import TypeVar
 
 from fastmcp.utilities.json_schema_type import json_schema_to_type
 
 __all__ = ["ElicitRequestParams", "ElicitResult", "ElicitationHandler"]
 
-T = TypeVar("T")
+T = TypeVar("T", default=Any)
 
 
 class ElicitResult(MCPElicitResult, Generic[T]):

src/fastmcp/server/context.py

@@ -10,7 +10,7 @@ from contextlib import contextmanager
 from contextvars import ContextVar, Token
 from dataclasses import dataclass
 from enum import Enum
-from typing import Any, Literal, TypeVar, cast, get_origin, overload
+from typing import Any, Literal, cast, get_origin, overload
 
 from mcp import LoggingLevel, ServerSession
 from mcp.server.lowlevel.helper_types import ReadResourceContents
@@ -31,6 +31,7 @@ from mcp.types import (
 from mcp.types import CreateMessageRequestParams as SamplingParams
 from pydantic.networks import AnyUrl
 from starlette.requests import Request
+from typing_extensions import TypeVar
 
 import fastmcp.server.dependencies
 from fastmcp import settings
@@ -47,7 +48,7 @@ from fastmcp.utilities.types import get_cached_typeadapter
 
 logger = get_logger(__name__)
 
-T = TypeVar("T")
+T = TypeVar("T", default=Any)
 _current_context: ContextVar[Context | None] = ContextVar("context", default=None)  # type: ignore[assignment]
 _flush_lock = asyncio.Lock()
 

src/fastmcp/server/dependencies.py

@@ -1,11 +1,12 @@
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, ParamSpec, TypeVar
+from typing import TYPE_CHECKING, Any, ParamSpec
 
 from mcp.server.auth.middleware.auth_context import (
     get_access_token as _sdk_get_access_token,
 )
 from starlette.requests import Request
+from typing_extensions import TypeVar
 
 from fastmcp.server.auth import AccessToken
 
@@ -13,7 +14,7 @@ if TYPE_CHECKING:
     from fastmcp.server.context import Context
 
 P = ParamSpec("P")
-R = TypeVar("R")
+R = TypeVar("R", default=Any)
 
 __all__ = [
     "get_context",

src/fastmcp/server/elicitation.py

@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 from dataclasses import dataclass
-from typing import Any, Generic, Literal, TypeVar
+from typing import Any, Generic, Literal
 
 from mcp.server.elicitation import (
     CancelledElicitation,
@@ -10,6 +10,7 @@ from mcp.server.elicitation import (
 from pydantic import BaseModel
 from pydantic.json_schema import GenerateJsonSchema, JsonSchemaValue
 from pydantic_core import core_schema
+from typing_extensions import TypeVar
 
 from fastmcp.utilities.json_schema import compress_schema
 from fastmcp.utilities.logging import get_logger
@@ -25,7 +26,7 @@ __all__ = [
 
 logger = get_logger(__name__)
 
-T = TypeVar("T")
+T = TypeVar("T", default=Any)
 
 
 class ElicitationJsonSchema(GenerateJsonSchema):

src/fastmcp/server/middleware/middleware.py

@@ -11,11 +11,11 @@ from typing import (
     Generic,
     Literal,
     Protocol,
-    TypeVar,
     runtime_checkable,
 )
 
 import mcp.types as mt
+from typing_extensions import TypeVar
 
 from fastmcp.prompts.prompt import Prompt
 from fastmcp.resources.resource import Resource
@@ -34,8 +34,8 @@ __all__ = [
 logger = logging.getLogger(__name__)
 
 
-T = TypeVar("T")
-R = TypeVar("R", covariant=True)
+T = TypeVar("T", default=Any)
+R = TypeVar("R", covariant=True, default=Any)
 
 
 @runtime_checkable

src/fastmcp/tools/tool.py

@@ -10,7 +10,6 @@ from typing import (
     Any,
     Generic,
     Literal,
-    TypeVar,
     get_type_hints,
 )
 
@@ -19,6 +18,7 @@ import pydantic_core
 from mcp.types import ContentBlock, TextContent, ToolAnnotations
 from mcp.types import Tool as MCPTool
 from pydantic import Field, PydanticSchemaGenerationError
+from typing_extensions import TypeVar
 
 import fastmcp
 from fastmcp.server.dependencies import get_context
@@ -41,7 +41,7 @@ if TYPE_CHECKING:
 
 logger = get_logger(__name__)
 
-T = TypeVar("T")
+T = TypeVar("T", default=Any)
 
 
 @dataclass

src/fastmcp/utilities/components.py

@@ -1,15 +1,15 @@
 from __future__ import annotations
 
 from collections.abc import Sequence
-from typing import Annotated, Any, TypedDict, TypeVar
+from typing import Annotated, Any, TypedDict
 
 from pydantic import BeforeValidator, Field, PrivateAttr
-from typing_extensions import Self
+from typing_extensions import Self, TypeVar
 
 import fastmcp
 from fastmcp.utilities.types import FastMCPBaseModel
 
-T = TypeVar("T")
+T = TypeVar("T", default=Any)
 
 
 class FastMCPMeta(TypedDict, total=False):

src/fastmcp/utilities/types.py

@@ -13,7 +13,6 @@ from typing import (
     Any,
     Protocol,
     TypeAlias,
-    TypeVar,
     Union,
     get_args,
     get_origin,
@@ -23,8 +22,9 @@ from typing import (
 import mcp.types
 from mcp.types import Annotations, ContentBlock, ModelPreferences, SamplingMessage
 from pydantic import AnyUrl, BaseModel, ConfigDict, Field, TypeAdapter, UrlConstraints
+from typing_extensions import TypeVar
 
-T = TypeVar("T")
+T = TypeVar("T", default=Any)
 
 # sentinel values for optional arguments
 NotSet = ...