refactor: move inline imports to module level (#1893)

src/mcp/client/__main__.py

@@ -1,6 +1,7 @@
 import argparse
 import logging
 import sys
+import warnings
 from functools import partial
 from urllib.parse import urlparse
 
@@ -15,8 +16,6 @@ from mcp.shared.message import SessionMessage
 from mcp.shared.session import RequestResponder
 
 if not sys.warnoptions:
-    import warnings
-
     warnings.simplefilter("ignore")
 
 logging.basicConfig(level=logging.INFO)

src/mcp/client/auth/extensions/client_credentials.py

@@ -9,6 +9,7 @@ Provides OAuth providers for machine-to-machine authentication flows:
 """
 
 import time
+import warnings
 from collections.abc import Awaitable, Callable
 from typing import Any, Literal
 from uuid import uuid4
@@ -409,8 +410,6 @@ class RFC7523OAuthClientProvider(OAuthClientProvider):
         timeout: float = 300.0,
         jwt_parameters: JWTParameters | None = None,
     ) -> None:
-        import warnings
-
         warnings.warn(
             "RFC7523OAuthClientProvider is deprecated. Use ClientCredentialsOAuthProvider "
             "or PrivateKeyJWTOAuthProvider instead.",

src/mcp/server/__main__.py

@@ -1,6 +1,7 @@
 import importlib.metadata
 import logging
 import sys
+import warnings
 
 import anyio
 
@@ -10,8 +11,6 @@ from mcp.server.stdio import stdio_server
 from mcp.types import ServerCapabilities
 
 if not sys.warnoptions:
-    import warnings
-
     warnings.simplefilter("ignore")
 
 logging.basicConfig(level=logging.INFO)

src/mcp/server/lowlevel/server.py

@@ -74,6 +74,7 @@ import logging
 import warnings
 from collections.abc import AsyncIterator, Awaitable, Callable, Iterable
 from contextlib import AbstractAsyncContextManager, AsyncExitStack, asynccontextmanager
+from importlib.metadata import version as importlib_version
 from typing import Any, Generic, TypeAlias, cast
 
 import anyio
@@ -173,9 +174,7 @@ class Server(Generic[LifespanResultT, RequestT]):
 
         def pkg_version(package: str) -> str:
             try:
-                from importlib.metadata import version
+                return importlib_version(package)
-
-                return version(package)
             except Exception:  # pragma: no cover
                 pass
 

tests/client/auth/extensions/test_client_credentials.py

@@ -1,4 +1,5 @@
 import urllib.parse
+import warnings
 
 import jwt
 import pytest
@@ -60,8 +61,6 @@ def rfc7523_oauth_provider(client_metadata: OAuthClientMetadata, mock_storage: M
         """Mock callback handler."""
         return "test_auth_code", "test_state"
 
-    import warnings
-
     with warnings.catch_warnings():
         warnings.simplefilter("ignore", DeprecationWarning)
         return RFC7523OAuthClientProvider(

tests/client/test_auth.py

@@ -5,7 +5,7 @@ Tests for refactored OAuth client authentication implementation.
 import base64
 import time
 from unittest import mock
-from urllib.parse import unquote
+from urllib.parse import parse_qs, quote, unquote, urlparse
 
 import httpx
 import pytest
@@ -27,6 +27,8 @@ from mcp.client.auth.utils import (
     is_valid_client_metadata_url,
     should_use_client_metadata_url,
 )
+from mcp.server.auth.routes import build_metadata
+from mcp.server.auth.settings import ClientRegistrationOptions, RevocationOptions
 from mcp.shared.auth import (
     OAuthClientInformationFull,
     OAuthClientMetadata,
@@ -758,8 +760,6 @@ class TestProtectedResourceMetadata:
         content = request.content.decode()
         assert "resource=" in content
         # Check URL-encoded resource parameter
-        from urllib.parse import quote
-
         expected_resource = quote(oauth_provider.context.get_resource_url(), safe="")
         assert f"resource={expected_resource}" in content
 
@@ -1226,8 +1226,6 @@ class TestAuthFlow:
                 "%3A", ":"
             ).replace("+", " ")
             # Extract state from redirect URL
-            from urllib.parse import parse_qs, urlparse
-
             parsed = urlparse(url)
             params = parse_qs(parsed.query)
             captured_state = params.get("state", [None])[0]
@@ -1336,9 +1334,6 @@ def test_build_metadata(
     registration_endpoint: str,
     revocation_endpoint: str,
 ):
-    from mcp.server.auth.routes import build_metadata
-    from mcp.server.auth.settings import ClientRegistrationOptions, RevocationOptions
-
     metadata = build_metadata(
         issuer_url=AnyHttpUrl(issuer_url),
         service_documentation_url=AnyHttpUrl(service_documentation_url),

tests/client/test_http_unicode.py

@@ -7,12 +7,20 @@ Verifies that Unicode text is correctly transmitted and received in both directi
 
 import multiprocessing
 import socket
-from collections.abc import Generator
+from collections.abc import AsyncGenerator, Generator
+from contextlib import asynccontextmanager
+from typing import Any
 
 import pytest
+from starlette.applications import Starlette
+from starlette.routing import Mount
 
+import mcp.types as types
 from mcp.client.session import ClientSession
 from mcp.client.streamable_http import streamable_http_client
+from mcp.server import Server
+from mcp.server.streamable_http_manager import StreamableHTTPSessionManager
+from mcp.types import TextContent, Tool
 from tests.test_helpers import wait_for_server
 
 # Test constants with various Unicode characters
@@ -37,19 +45,7 @@ UNICODE_TEST_STRINGS = {
 
 def run_unicode_server(port: int) -> None:  # pragma: no cover
     """Run the Unicode test server in a separate process."""
-    # Import inside the function since this runs in a separate process
-    from collections.abc import AsyncGenerator
-    from contextlib import asynccontextmanager
-    from typing import Any
-
     import uvicorn
-    from starlette.applications import Starlette
-    from starlette.routing import Mount
-
-    import mcp.types as types
-    from mcp.server import Server
-    from mcp.server.streamable_http_manager import StreamableHTTPSessionManager
-    from mcp.types import TextContent, Tool
 
     # Need to recreate the server setup in this process
     server = Server(name="unicode_test_server")

tests/client/test_list_roots_callback.py

@@ -2,6 +2,7 @@ import pytest
 from pydantic import FileUrl
 
 from mcp.client.session import ClientSession
+from mcp.server.fastmcp import FastMCP
 from mcp.server.fastmcp.server import Context
 from mcp.server.session import ServerSession
 from mcp.shared.context import RequestContext
@@ -13,8 +14,6 @@ from mcp.types import ListRootsResult, Root, TextContent
 
 @pytest.mark.anyio
 async def test_list_roots_callback():
-    from mcp.server.fastmcp import FastMCP
-
     server = FastMCP("test")
 
     callback_return = ListRootsResult(

tests/client/test_logging_callback.py

@@ -3,6 +3,7 @@ from typing import Any, Literal
 import pytest
 
 import mcp.types as types
+from mcp.server.fastmcp import FastMCP
 from mcp.shared.memory import (
     create_connected_server_and_client_session as create_session,
 )
@@ -23,8 +24,6 @@ class LoggingCollector:
 
 @pytest.mark.anyio
 async def test_logging_callback():
-    from mcp.server.fastmcp import FastMCP
-
     server = FastMCP("test")
     logging_collector = LoggingCollector()
 

tests/client/test_output_schema_validation.py

@@ -1,8 +1,10 @@
+import inspect
 import logging
 from contextlib import contextmanager
 from typing import Any
 from unittest.mock import patch
 
+import jsonschema
 import pytest
 
 from mcp.server.lowlevel import Server
@@ -19,15 +21,11 @@ def bypass_server_output_validation():
     This simulates a malicious or non-compliant server that doesn't validate
     its outputs, allowing us to test client-side validation.
     """
-    import jsonschema
-
     # Save the original validate function
     original_validate = jsonschema.validate
 
     # Create a mock that tracks which module is calling it
     def selective_mock(instance: Any = None, schema: Any = None, *args: Any, **kwargs: Any) -> None:
-        import inspect
-
         # Check the call stack to see where this is being called from
         for frame_info in inspect.stack():
             # If called from the server module, skip validation

tests/client/test_sampling_callback.py

@@ -1,6 +1,7 @@
 import pytest
 
 from mcp.client.session import ClientSession
+from mcp.server.fastmcp import FastMCP
 from mcp.shared.context import RequestContext
 from mcp.shared.memory import (
     create_connected_server_and_client_session as create_session,
@@ -17,8 +18,6 @@ from mcp.types import (
 
 @pytest.mark.anyio
 async def test_sampling_callback():
-    from mcp.server.fastmcp import FastMCP
-
     server = FastMCP("test")
 
     callback_return = CreateMessageResult(
@@ -63,8 +62,6 @@ async def test_sampling_callback():
 @pytest.mark.anyio
 async def test_create_message_backwards_compat_single_content():
     """Test backwards compatibility: create_message without tools returns single content."""
-    from mcp.server.fastmcp import FastMCP
-
     server = FastMCP("test")
 
     # Callback returns single content (text)

tests/client/test_session_group.py

@@ -1,6 +1,7 @@
 import contextlib
 from unittest import mock
 
+import httpx
 import pytest
 
 import mcp
@@ -356,8 +357,6 @@ class TestClientSessionGroup:
                     assert isinstance(server_params_instance, StreamableHttpParameters)
                     # Verify streamable_http_client was called with url, httpx_client, and terminate_on_close
                     # The http_client is created by the real create_mcp_http_client
-                    import httpx
-
                     call_args = mock_specific_client_func.call_args
                     assert call_args.kwargs["url"] == server_params_instance.url
                     assert call_args.kwargs["terminate_on_close"] == server_params_instance.terminate_on_close

tests/client/test_stdio.py

@@ -10,7 +10,12 @@ import anyio
 import pytest
 
 from mcp.client.session import ClientSession
-from mcp.client.stdio import StdioServerParameters, _create_platform_compatible_process, stdio_client
+from mcp.client.stdio import (
+    StdioServerParameters,
+    _create_platform_compatible_process,
+    _terminate_process_tree,
+    stdio_client,
+)
 from mcp.shared.exceptions import McpError
 from mcp.shared.message import SessionMessage
 from mcp.types import CONNECTION_CLOSED, JSONRPCMessage, JSONRPCRequest, JSONRPCResponse
@@ -312,8 +317,6 @@ class TestChildProcessCleanup:
 
             # Terminate using our function
             print("Terminating process and children...")
-            from mcp.client.stdio import _terminate_process_tree
-
             await _terminate_process_tree(proc)
 
             # Verify processes stopped
@@ -413,8 +416,6 @@ class TestChildProcessCleanup:
                     assert new_size > initial_size, f"{name} process should be writing"
 
             # Terminate the whole tree
-            from mcp.client.stdio import _terminate_process_tree
-
             await _terminate_process_tree(proc)
 
             # Verify all stopped
@@ -494,8 +495,6 @@ class TestChildProcessCleanup:
                 assert size2 > size1, "Child should be writing"
 
             # Terminate - this will kill the process group even if parent exits first
-            from mcp.client.stdio import _terminate_process_tree
-
             await _terminate_process_tree(proc)
 
             # Verify child stopped

tests/server/auth/test_error_handling.py

@@ -2,6 +2,9 @@
 Tests for OAuth error handling in the auth handlers.
 """
 
+import base64
+import hashlib
+import secrets
 import unittest.mock
 from typing import Any
 from urllib.parse import parse_qs, urlparse
@@ -14,6 +17,7 @@ from starlette.applications import Starlette
 
 from mcp.server.auth.provider import AuthorizeError, RegistrationError, TokenError
 from mcp.server.auth.routes import create_auth_routes
+from mcp.server.auth.settings import ClientRegistrationOptions, RevocationOptions
 from tests.server.fastmcp.auth.test_auth_integration import MockOAuthProvider
 
 
@@ -25,8 +29,6 @@ def oauth_provider():
 
 @pytest.fixture
 def app(oauth_provider: MockOAuthProvider):
-    from mcp.server.auth.settings import ClientRegistrationOptions, RevocationOptions
-
     # Enable client registration
     client_registration_options = ClientRegistrationOptions(enabled=True)
     revocation_options = RevocationOptions(enabled=True)
@@ -53,10 +55,6 @@ def client(app: Starlette):
 @pytest.fixture
 def pkce_challenge():
     """Create a PKCE challenge with code_verifier and code_challenge."""
-    import base64
-    import hashlib
-    import secrets
-
     # Generate a code verifier
     code_verifier = secrets.token_urlsafe(64)[:128]
 

tests/server/auth/test_protected_resource.py

@@ -2,6 +2,8 @@
 Integration tests for MCP Oauth Protected Resource.
 """
 
+from urllib.parse import urlparse
+
 import httpx
 import pytest
 from inline_snapshot import snapshot
@@ -159,8 +161,6 @@ class TestRouteConsistency:
         )
 
         # Extract path from metadata URL
-        from urllib.parse import urlparse
-
         metadata_path = urlparse(str(metadata_url)).path
 
         # Verify consistency
@@ -181,8 +181,6 @@ class TestRouteConsistency:
 
         # Test URL generation
         metadata_url = build_resource_metadata_url(resource_url_obj)
-        from urllib.parse import urlparse
-
         url_path = urlparse(str(metadata_url)).path
 
         # Test route creation

tests/server/fastmcp/auth/test_auth_integration.py

@@ -1258,8 +1258,6 @@ class TestAuthEndpoints:
         )
 
         # Send base64 without colon (invalid format)
-        import base64
-
         invalid_creds = base64.b64encode(b"no-colon-here").decode()
         response = await test_client.post(
             "/token",
@@ -1306,8 +1304,6 @@ class TestAuthEndpoints:
         )
 
         # Send different client_id in Basic auth header
-        import base64
-
         wrong_creds = base64.b64encode(f"wrong-client-id:{client_info['client_secret']}".encode()).decode()
         response = await test_client.post(
             "/token",

tests/server/fastmcp/test_func_metadata.py

@@ -5,13 +5,14 @@
 # pyright: reportUnknownLambdaType=false
 from collections.abc import Callable
 from dataclasses import dataclass
-from typing import Annotated, Any, Final, TypedDict
+from typing import Annotated, Any, Final, NamedTuple, TypedDict
 
 import annotated_types
 import pytest
 from dirty_equals import IsPartialDict
 from pydantic import BaseModel, Field
 
+from mcp.server.fastmcp.exceptions import InvalidSignature
 from mcp.server.fastmcp.utilities.func_metadata import func_metadata
 from mcp.types import CallToolResult
 
@@ -558,7 +559,6 @@ async def test_str_annotation_runtime_validation():
 
 def test_structured_output_requires_return_annotation():
     """Test that structured_output=True requires a return annotation"""
-    from mcp.server.fastmcp.exceptions import InvalidSignature
 
     def func_no_annotation():  # pragma: no cover
         return "hello"
@@ -881,8 +881,6 @@ def test_tool_call_result_annotated_is_structured_and_invalid():
 def test_tool_call_result_in_optional_is_rejected():
     """Test that Optional[CallToolResult] raises InvalidSignature"""
 
-    from mcp.server.fastmcp.exceptions import InvalidSignature
-
     def func_optional_call_tool_result() -> CallToolResult | None:  # pragma: no cover
         return CallToolResult(content=[])
 
@@ -896,8 +894,6 @@ def test_tool_call_result_in_optional_is_rejected():
 def test_tool_call_result_in_union_is_rejected():
     """Test that Union[str, CallToolResult] raises InvalidSignature"""
 
-    from mcp.server.fastmcp.exceptions import InvalidSignature
-
     def func_union_call_tool_result() -> str | CallToolResult:  # pragma: no cover
         return CallToolResult(content=[])
 
@@ -910,7 +906,6 @@ def test_tool_call_result_in_union_is_rejected():
 
 def test_tool_call_result_in_pipe_union_is_rejected():
     """Test that str | CallToolResult raises InvalidSignature"""
-    from mcp.server.fastmcp.exceptions import InvalidSignature
 
     def func_pipe_union_call_tool_result() -> str | CallToolResult:  # pragma: no cover
         return CallToolResult(content=[])
@@ -985,9 +980,6 @@ def test_structured_output_nested_models():
 
 def test_structured_output_unserializable_type_error():
     """Test error when structured_output=True is used with unserializable types"""
-    from typing import NamedTuple
-
-    from mcp.server.fastmcp.exceptions import InvalidSignature
 
     # Test with a class that has non-serializable default values
     class ConfigWithCallable:
@@ -1185,8 +1177,6 @@ def test_basemodel_reserved_names_with_json_preparsing():
 
 
 def test_disallowed_type_qualifier():
-    from mcp.server.fastmcp.exceptions import InvalidSignature
-
     def func_disallowed_qualifier() -> Final[int]:  # type: ignore
         pass  # pragma: no cover
 

tests/server/fastmcp/test_integration.py

@@ -51,8 +51,10 @@ from mcp.types import (
     NotificationParams,
     ProgressNotification,
     ProgressNotificationParams,
+    PromptReference,
     ReadResourceResult,
     ResourceListChangedNotification,
+    ResourceTemplateReference,
     ServerNotification,
     ServerRequest,
     TextContent,
@@ -583,8 +585,6 @@ async def test_completion(server_transport: str, server_url: str) -> None:
             assert result.capabilities.prompts is not None
 
             # Test resource completion
-            from mcp.types import ResourceTemplateReference
-
             completion_result = await session.complete(
                 ref=ResourceTemplateReference(type="ref/resource", uri="github://repos/{owner}/{repo}"),
                 argument={"name": "repo", "value": ""},
@@ -600,8 +600,6 @@ async def test_completion(server_transport: str, server_url: str) -> None:
             assert "specification" in completion_result.completion.values
 
             # Test prompt completion
-            from mcp.types import PromptReference
-
             completion_result = await session.complete(
                 ref=PromptReference(type="ref/prompt", name="review_code"),
                 argument={"name": "language", "value": "py"},
@@ -644,8 +642,6 @@ async def test_fastmcp_quickstart(server_transport: str, server_url: str) -> Non
             assert tool_result.content[0].text == "30"
 
             # Test greeting resource directly
-            from pydantic import AnyUrl
-
             resource_result = await session.read_resource(AnyUrl("greeting://Alice"))
             assert len(resource_result.contents) == 1
             assert isinstance(resource_result.contents[0], TextResourceContents)

tests/server/fastmcp/test_server.py

@@ -5,9 +5,11 @@ from unittest.mock import patch
 
 import pytest
 from pydantic import BaseModel
+from starlette.applications import Starlette
 from starlette.routing import Mount, Route
 
 from mcp.server.fastmcp import Context, FastMCP
+from mcp.server.fastmcp.exceptions import ToolError
 from mcp.server.fastmcp.prompts.base import Message, UserMessage
 from mcp.server.fastmcp.resources import FileResource, FunctionResource
 from mcp.server.fastmcp.utilities.types import Audio, Image
@@ -51,8 +53,6 @@ class TestServer:
     @pytest.mark.anyio
     async def test_sse_app_returns_starlette_app(self):
         """Test that sse_app returns a Starlette application with correct routes."""
-        from starlette.applications import Starlette
-
         mcp = FastMCP("test", host="0.0.0.0")  # Use 0.0.0.0 to avoid auto DNS protection
         app = mcp.sse_app()
 
@@ -617,8 +617,6 @@ class TestServerTools:
     @pytest.mark.anyio
     async def test_remove_nonexistent_tool(self):
         """Test that removing a non-existent tool raises ToolError."""
-        from mcp.server.fastmcp.exceptions import ToolError
-
         mcp = FastMCP()
 
         with pytest.raises(ToolError, match="Unknown tool: nonexistent"):

tests/server/fastmcp/test_url_elicitation.py

@@ -2,10 +2,11 @@
 
 import anyio
 import pytest
+from pydantic import BaseModel, Field
 
 from mcp import types
 from mcp.client.session import ClientSession
-from mcp.server.elicitation import CancelledElicitation, DeclinedElicitation
+from mcp.server.elicitation import CancelledElicitation, DeclinedElicitation, elicit_url
 from mcp.server.fastmcp import Context, FastMCP
 from mcp.server.session import ServerSession
 from mcp.shared.context import RequestContext
@@ -110,8 +111,6 @@ async def test_url_elicitation_cancel():
 @pytest.mark.anyio
 async def test_url_elicitation_helper_function():
     """Test the elicit_url helper function."""
-    from mcp.server.elicitation import elicit_url
-
     mcp = FastMCP(name="URLElicitationHelperServer")
 
     @mcp.tool(description="Tool using elicit_url helper")
@@ -180,8 +179,6 @@ async def test_url_no_content_in_response():
 @pytest.mark.anyio
 async def test_form_mode_still_works():
     """Ensure form mode elicitation still works after SEP 1036."""
-    from pydantic import BaseModel, Field
-
     mcp = FastMCP(name="FormModeBackwardCompatServer")
 
     class NameSchema(BaseModel):
@@ -267,8 +264,6 @@ async def test_url_elicitation_required_error_code():
 @pytest.mark.anyio
 async def test_elicit_url_typed_results():
     """Test that elicit_url returns properly typed result objects."""
-    from mcp.server.elicitation import elicit_url
-
     mcp = FastMCP(name="TypedResultsServer")
 
     @mcp.tool(description="Test declined result")
@@ -329,8 +324,6 @@ async def test_elicit_url_typed_results():
 @pytest.mark.anyio
 async def test_deprecated_elicit_method():
     """Test the deprecated elicit() method for backward compatibility."""
-    from pydantic import BaseModel, Field
-
     mcp = FastMCP(name="DeprecatedElicitServer")
 
     class EmailSchema(BaseModel):