Python lint: Ruff rules for pylint and code complexity

Author: cclauss

README.md

@@ -643,7 +643,7 @@ The lifespan API provides:
 
 ```python
 import mcp.server.stdio
-import mcp.types as types
+from mcp import types
 from mcp.server.lowlevel import NotificationOptions, Server
 from mcp.server.models import InitializationOptions
 

examples/servers/simple-prompt/mcp_simple_prompt/server.py

@@ -1,6 +1,6 @@
 import anyio
 import click
-import mcp.types as types
+from mcp import types
 from mcp.server.lowlevel import Server
 
 

examples/servers/simple-resource/mcp_simple_resource/server.py

@@ -1,6 +1,6 @@
 import anyio
 import click
-import mcp.types as types
+from mcp import types
 from mcp.server.lowlevel import Server
 from pydantic import AnyUrl
 

pyproject.toml

@@ -90,18 +90,26 @@ venvPath = "."
 venv = ".venv"
 strict = ["src/mcp/**/*.py"]
 
-[tool.ruff.lint]
-select = ["C4", "E", "F", "I", "PERF", "UP"]
-ignore = ["PERF203"]
-
 [tool.ruff]
 line-length = 88
 target-version = "py310"
 
+[tool.ruff.lint]
+select = ["C4", "C90", "E", "F", "I", "PERF", "PL", "UP"]
+ignore = ["PERF203"]
+mccabe.max-complexity = 13  # Default is 10
+
 [tool.ruff.lint.per-file-ignores]
 "__init__.py" = ["F401"]
 "tests/server/fastmcp/test_func_metadata.py" = ["E501"]
 
+[tool.ruff.lint.pylint]
+allow-magic-value-types = ["bytes", "float", "int", "str"]
+max-args = 20        # Default is 5
+max-branches = 14    # Default is 12
+max-returns = 7      # Default is 6
+max-statements = 69  # Default is 50
+
 [tool.uv.workspace]
 members = ["examples/servers/*"]
 

src/mcp/client/__main__.py

@@ -7,7 +7,7 @@
 import anyio
 from anyio.streams.memory import MemoryObjectReceiveStream, MemoryObjectSendStream
 
-import mcp.types as types
+from mcp import types
 from mcp.client.session import ClientSession
 from mcp.client.sse import sse_client
 from mcp.client.stdio import StdioServerParameters, stdio_client

src/mcp/client/session.py

@@ -5,7 +5,7 @@
 from anyio.streams.memory import MemoryObjectReceiveStream, MemoryObjectSendStream
 from pydantic import AnyUrl, TypeAdapter
 
-import mcp.types as types
+from mcp import types
 from mcp.shared.context import RequestContext
 from mcp.shared.message import SessionMessage
 from mcp.shared.session import BaseSession, ProgressFnT, RequestResponder

src/mcp/server/lowlevel/server.py

@@ -78,11 +78,10 @@ async def main():
 from anyio.streams.memory import MemoryObjectReceiveStream, MemoryObjectSendStream
 from pydantic import AnyUrl
 
-import mcp.types as types
+from mcp import types
 from mcp.server.lowlevel.helper_types import ReadResourceContents
 from mcp.server.models import InitializationOptions
 from mcp.server.session import ServerSession
-from mcp.server.stdio import stdio_server as stdio_server
 from mcp.shared.context import RequestContext
 from mcp.shared.exceptions import McpError
 from mcp.shared.message import SessionMessage

src/mcp/server/session.py

@@ -45,7 +45,7 @@ async def handle_list_prompts(ctx: RequestContext) -> list[types.Prompt]:
 from anyio.streams.memory import MemoryObjectReceiveStream, MemoryObjectSendStream
 from pydantic import AnyUrl
 
-import mcp.types as types
+from mcp import types
 from mcp.server.models import InitializationOptions
 from mcp.shared.message import ServerMessageMetadata, SessionMessage
 from mcp.shared.session import (

src/mcp/shared/memory.py

@@ -10,7 +10,7 @@
 import anyio
 from anyio.streams.memory import MemoryObjectReceiveStream, MemoryObjectSendStream
 
-import mcp.types as types
+from mcp import types
 from mcp.client.session import (
     ClientSession,
     ListRootsFnT,

tests/client/test_logging_callback.py

@@ -2,7 +2,7 @@
 
 import pytest
 
-import mcp.types as types
+from mcp import types
 from mcp.shared.memory import (
     create_connected_server_and_client_session as create_session,
 )