Deprecate roots, sampling, and logging methods per SEP-2577 (#2926)

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Marcelo Trylesinski 2026-06-20 17:25:41 +01:00 • committed by GitHub
commit 4573e4ac33
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44 changed files with 206 additions and 123 deletions

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@ -360,7 +360,7 @@ mcp = MCPServer(name="Progress Example")
@mcp.tool()
async def long_running_task(task_name: str, ctx: Context, steps: int = 5) -> str:
"""Execute a task with progress updates."""
await ctx.info(f"Starting: {task_name}")
await ctx.info(f"Starting: {task_name}") # pyright: ignore[reportDeprecated]
for i in range(steps):
progress = (i + 1) / steps
@ -369,7 +369,7 @@ async def long_running_task(task_name: str, ctx: Context, steps: int = 5) -> str
total=1.0,
message=f"Step {i + 1}/{steps}",
)
await ctx.debug(f"Completed step {i + 1}")
await ctx.debug(f"Completed step {i + 1}") # pyright: ignore[reportDeprecated]
return f"Task '{task_name}' completed"
```
@ -707,7 +707,7 @@ mcp = MCPServer(name="Progress Example")
@mcp.tool()
async def long_running_task(task_name: str, ctx: Context, steps: int = 5) -> str:
"""Execute a task with progress updates."""
await ctx.info(f"Starting: {task_name}")
await ctx.info(f"Starting: {task_name}") # pyright: ignore[reportDeprecated]
for i in range(steps):
progress = (i + 1) / steps
@ -716,7 +716,7 @@ async def long_running_task(task_name: str, ctx: Context, steps: int = 5) -> str
total=1.0,
message=f"Step {i + 1}/{steps}",
)
await ctx.debug(f"Completed step {i + 1}")
await ctx.debug(f"Completed step {i + 1}") # pyright: ignore[reportDeprecated]
return f"Task '{task_name}' completed"
```
@ -948,7 +948,7 @@ async def generate_poem(topic: str, ctx: Context) -> str:
"""Generate a poem using LLM sampling."""
prompt = f"Write a short poem about {topic}"
result = await ctx.session.create_message(
result = await ctx.session.create_message( # pyright: ignore[reportDeprecated]
messages=[
SamplingMessage(
role="user",
@ -982,10 +982,10 @@ mcp = MCPServer(name="Notifications Example")
async def process_data(data: str, ctx: Context) -> str:
"""Process data with logging."""
# Different log levels
await ctx.debug(f"Debug: Processing '{data}'")
await ctx.info("Info: Starting processing")
await ctx.warning("Warning: This is experimental")
await ctx.error("Error: (This is just a demo)")
await ctx.debug(f"Debug: Processing '{data}'") # pyright: ignore[reportDeprecated]
await ctx.info("Info: Starting processing") # pyright: ignore[reportDeprecated]
await ctx.warning("Warning: This is experimental") # pyright: ignore[reportDeprecated]
await ctx.error("Error: (This is just a demo)") # pyright: ignore[reportDeprecated]
# Notify about resource changes
await ctx.session.send_resource_list_changed()

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@ -1245,7 +1245,26 @@ Tasks are expected to return as a separate MCP extension in a future release.
## Deprecations
<!-- Add deprecations below -->
### Roots, Sampling, and Logging methods deprecated (SEP-2577)
[SEP-2577](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2577) deprecates the Roots, Sampling, and Logging features as of the 2026-07-28 spec. The deprecation is advisory only: there are no wire-level changes, capability negotiation is unchanged, and every method keeps working for sessions negotiating 2025-11-25 and earlier.
The user-facing methods for these features now carry `typing_extensions.deprecated`, so type checkers, IDEs, and the runtime surface a deprecation warning where they are called:
- Sampling: `ServerSession.create_message()`, `ClientPeer.sample()`
- Roots: `ServerSession.list_roots()`, `ClientPeer.list_roots()`, `ClientSession.send_roots_list_changed()`, `Client.send_roots_list_changed()`
- Logging: `ServerSession.send_log_message()`, `Connection.log()`, `ClientSession.set_logging_level()`, `Client.set_logging_level()`, `mcp.server.context.Context.log()` (the lowlevel `Context`), and the `MCPServer` `Context` helpers `log()`, `debug()`, `info()`, `warning()`, `error()`
The runtime warning is emitted as `mcp.MCPDeprecationWarning`, which subclasses `UserWarning` (not `DeprecationWarning`) so it is visible by default. To silence it, filter that category:
```python
import warnings
from mcp import MCPDeprecationWarning
warnings.filterwarnings("ignore", category=MCPDeprecationWarning)
```
No migration is required during the deprecation window. New code should avoid building on these features, since they may be removed in a future spec version.
## Bug Fixes

View file

@ -143,13 +143,13 @@ def test_multiple_content_types() -> list[TextContent | ImageContent | EmbeddedR
@mcp.tool()
async def test_tool_with_logging(ctx: Context) -> str:
"""Tests tool that emits log messages during execution"""
await ctx.info("Tool execution started")
await ctx.info("Tool execution started") # pyright: ignore[reportDeprecated]
await asyncio.sleep(0.05)
await ctx.info("Tool processing data")
await ctx.info("Tool processing data") # pyright: ignore[reportDeprecated]
await asyncio.sleep(0.05)
await ctx.info("Tool execution completed")
await ctx.info("Tool execution completed") # pyright: ignore[reportDeprecated]
return "Tool with logging executed successfully"
@ -176,7 +176,7 @@ async def test_sampling(prompt: str, ctx: Context) -> str:
"""Tests server-initiated sampling (LLM completion request)"""
try:
# Request sampling from client
result = await ctx.session.create_message(
result = await ctx.session.create_message( # pyright: ignore[reportDeprecated]
messages=[SamplingMessage(role="user", content=TextContent(type="text", text=prompt))],
max_tokens=100,
)
@ -314,13 +314,13 @@ def test_error_handling() -> str:
@mcp.tool()
async def test_reconnection(ctx: Context) -> str:
"""Tests SSE polling by closing stream mid-call (SEP-1699)"""
await ctx.info("Before disconnect")
await ctx.info("Before disconnect") # pyright: ignore[reportDeprecated]
await ctx.close_sse_stream()
await asyncio.sleep(0.2) # Wait for client to reconnect
await ctx.info("After reconnect")
await ctx.info("After reconnect") # pyright: ignore[reportDeprecated]
return "Reconnection test completed"

View file

@ -49,7 +49,7 @@ async def handle_call_tool(ctx: ServerRequestContext, params: types.CallToolRequ
# Send the specified number of notifications with the given interval
for i in range(count):
await ctx.session.send_log_message(
await ctx.session.send_log_message( # pyright: ignore[reportDeprecated]
level="info",
data=f"Notification {i + 1}/{count} from caller: {caller}",
logger="notification_stream",

View file

@ -54,7 +54,7 @@ async def handle_call_tool(ctx: ServerRequestContext, params: types.CallToolRequ
for i in range(count):
# Include more detailed message for resumability demonstration
notification_msg = f"[{i + 1}/{count}] Event from '{caller}' - Use Last-Event-ID to resume if disconnected"
await ctx.session.send_log_message(
await ctx.session.send_log_message( # pyright: ignore[reportDeprecated]
level="info",
data=notification_msg,
logger="notification_stream",

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@ -74,7 +74,7 @@ async def handle_call_tool(ctx: ServerRequestContext, params: types.CallToolRequ
content=[types.TextContent(type="text", text="Error: checkpoint_every must be between 1 and 20")]
)
await ctx.session.send_log_message(
await ctx.session.send_log_message( # pyright: ignore[reportDeprecated]
level="info",
data=f"Starting batch processing of {items} items...",
logger="process_batch",
@ -86,7 +86,7 @@ async def handle_call_tool(ctx: ServerRequestContext, params: types.CallToolRequ
await anyio.sleep(0.5)
# Report progress
await ctx.session.send_log_message(
await ctx.session.send_log_message( # pyright: ignore[reportDeprecated]
level="info",
data=f"[{i}/{items}] Processing item {i}",
logger="process_batch",
@ -95,7 +95,7 @@ async def handle_call_tool(ctx: ServerRequestContext, params: types.CallToolRequ
# Checkpoint: close stream to trigger client reconnect
if i % checkpoint_every == 0 and i < items:
await ctx.session.send_log_message(
await ctx.session.send_log_message( # pyright: ignore[reportDeprecated]
level="info",
data=f"Checkpoint at item {i} - closing SSE stream for polling",
logger="process_batch",

View file

@ -7,10 +7,10 @@ mcp = MCPServer(name="Notifications Example")
async def process_data(data: str, ctx: Context) -> str:
"""Process data with logging."""
# Different log levels
await ctx.debug(f"Debug: Processing '{data}'")
await ctx.info("Info: Starting processing")
await ctx.warning("Warning: This is experimental")
await ctx.error("Error: (This is just a demo)")
await ctx.debug(f"Debug: Processing '{data}'") # pyright: ignore[reportDeprecated]
await ctx.info("Info: Starting processing") # pyright: ignore[reportDeprecated]
await ctx.warning("Warning: This is experimental") # pyright: ignore[reportDeprecated]
await ctx.error("Error: (This is just a demo)") # pyright: ignore[reportDeprecated]
# Notify about resource changes
await ctx.session.send_resource_list_changed()

View file

@ -9,7 +9,7 @@ async def generate_poem(topic: str, ctx: Context) -> str:
"""Generate a poem using LLM sampling."""
prompt = f"Write a short poem about {topic}"
result = await ctx.session.create_message(
result = await ctx.session.create_message( # pyright: ignore[reportDeprecated]
messages=[
SamplingMessage(
role="user",

View file

@ -6,7 +6,7 @@ mcp = MCPServer(name="Progress Example")
@mcp.tool()
async def long_running_task(task_name: str, ctx: Context, steps: int = 5) -> str:
"""Execute a task with progress updates."""
await ctx.info(f"Starting: {task_name}")
await ctx.info(f"Starting: {task_name}") # pyright: ignore[reportDeprecated]
for i in range(steps):
progress = (i + 1) / steps
@ -15,6 +15,6 @@ async def long_running_task(task_name: str, ctx: Context, steps: int = 5) -> str
total=1.0,
message=f"Step {i + 1}/{steps}",
)
await ctx.debug(f"Completed step {i + 1}")
await ctx.debug(f"Completed step {i + 1}") # pyright: ignore[reportDeprecated]
return f"Task '{task_name}' completed"

View file

@ -213,6 +213,10 @@ filterwarnings = [
"error",
# pywin32 internal deprecation warning
"ignore:getargs.*The 'u' format is deprecated:DeprecationWarning",
# SEP-2577 deprecates the roots/sampling/logging methods; the SDK still calls
# them internally (e.g. `ctx.debug` -> `log` -> `send_log_message`), so the
# advisory warning is silenced. Tests asserting it opt back in with pytest.warns.
"ignore:.*is deprecated as of 2026-07-28 \\(SEP-2577\\).:mcp.MCPDeprecationWarning",
]
[tool.markdown.lint]

View file

@ -4,7 +4,7 @@ from .client.session_group import ClientSessionGroup
from .client.stdio import StdioServerParameters, stdio_client
from .server.session import ServerSession
from .server.stdio import stdio_server
from .shared.exceptions import MCPError, UrlElicitationRequiredError
from .shared.exceptions import MCPDeprecationWarning, MCPError, UrlElicitationRequiredError
from .types import (
CallToolRequest,
ClientCapabilities,
@ -96,6 +96,7 @@ __all__ = [
"ListToolsResult",
"LoggingLevel",
"LoggingMessageNotification",
"MCPDeprecationWarning",
"MCPError",
"Notification",
"PingRequest",

View file

@ -6,6 +6,8 @@ from contextlib import AsyncExitStack
from dataclasses import KW_ONLY, dataclass, field
from typing import Any
from typing_extensions import deprecated
from mcp.client._memory import InMemoryTransport
from mcp.client._transport import Transport
from mcp.client.session import ClientSession, ElicitationFnT, ListRootsFnT, LoggingFnT, MessageHandlerFnT, SamplingFnT
@ -13,6 +15,7 @@ from mcp.client.streamable_http import streamable_http_client
from mcp.server import Server
from mcp.server.mcpserver import MCPServer
from mcp.shared.dispatcher import ProgressFnT
from mcp.shared.exceptions import MCPDeprecationWarning
from mcp.types import (
CallToolResult,
CompleteResult,
@ -197,9 +200,10 @@ class Client:
message=message,
)
@deprecated("The logging capability is deprecated as of 2026-07-28 (SEP-2577).", category=MCPDeprecationWarning)
async def set_logging_level(self, level: LoggingLevel, *, meta: RequestParamsMeta | None = None) -> EmptyResult:
"""Set the logging level on the server."""
return await self.session.set_logging_level(level=level, meta=meta)
return await self.session.set_logging_level(level=level, meta=meta) # pyright: ignore[reportDeprecated]
async def list_resources(
self,
@ -314,7 +318,8 @@ class Client:
"""List available tools from the server."""
return await self.session.list_tools(params=PaginatedRequestParams(cursor=cursor, _meta=meta))
@deprecated("The roots capability is deprecated as of 2026-07-28 (SEP-2577).", category=MCPDeprecationWarning)
async def send_roots_list_changed(self) -> None:
"""Send a notification that the roots list has changed."""
# TODO(Marcelo): Currently, there is no way for the server to handle this. We should add support.
await self.session.send_roots_list_changed()
await self.session.send_roots_list_changed() # pyright: ignore[reportDeprecated]

View file

@ -10,13 +10,13 @@ import anyio
import anyio.abc
import anyio.lowlevel
from pydantic import BaseModel, TypeAdapter, ValidationError
from typing_extensions import Self, TypeVar
from typing_extensions import Self, TypeVar, deprecated
from mcp import types
from mcp.client._transport import ReadStream, WriteStream
from mcp.shared._compat import resync_tracer
from mcp.shared.dispatcher import CallOptions, DispatchContext, Dispatcher, ProgressFnT
from mcp.shared.exceptions import MCPError
from mcp.shared.exceptions import MCPDeprecationWarning, MCPError
from mcp.shared.jsonrpc_dispatcher import JSONRPCDispatcher
from mcp.shared.message import ClientMessageMetadata, SessionMessage
from mcp.shared.session import RequestResponder
@ -386,6 +386,7 @@ class ClientSession:
)
)
@deprecated("The logging capability is deprecated as of 2026-07-28 (SEP-2577).", category=MCPDeprecationWarning)
async def set_logging_level(
self,
level: types.LoggingLevel,
@ -550,6 +551,7 @@ class ClientSession:
return result
@deprecated("The roots capability is deprecated as of 2026-07-28 (SEP-2577).", category=MCPDeprecationWarning)
async def send_roots_list_changed(self) -> None:
"""Send a roots/list_changed notification."""
await self.send_notification(types.RootsListChangedNotification())

View file

@ -20,9 +20,10 @@ from typing import Any, TypeVar, overload
import anyio
from pydantic import BaseModel
from typing_extensions import deprecated
from mcp.shared.dispatcher import CallOptions, Outbound
from mcp.shared.exceptions import NoBackChannelError
from mcp.shared.exceptions import MCPDeprecationWarning, NoBackChannelError
from mcp.shared.peer import Meta, dump_params
from mcp.types import (
ClientCapabilities,
@ -209,6 +210,7 @@ class Connection:
"""
await self.send_raw_request("ping", dump_params(None, meta), opts)
@deprecated("The logging capability is deprecated as of 2026-07-28 (SEP-2577).", category=MCPDeprecationWarning)
async def log(self, level: LoggingLevel, data: Any, logger: str | None = None, *, meta: Meta | None = None) -> None:
"""Send a `notifications/message` log entry on the standalone stream. Best-effort."""
params: dict[str, Any] = {"level": level, "data": data}

View file

@ -3,12 +3,13 @@ from dataclasses import dataclass
from typing import Any, Generic, Protocol
from pydantic import BaseModel
from typing_extensions import TypeVar
from typing_extensions import TypeVar, deprecated
from mcp.server.connection import Connection
from mcp.server.session import ServerSession
from mcp.shared.context import BaseContext
from mcp.shared.dispatcher import DispatchContext
from mcp.shared.exceptions import MCPDeprecationWarning
from mcp.shared.message import CloseSSEStreamCallback
from mcp.shared.peer import Meta
from mcp.shared.transport_context import TransportContext
@ -92,6 +93,7 @@ class Context(BaseContext[TransportContext], Generic[LifespanT_co]):
"""
return self.transport.headers
@deprecated("The logging capability is deprecated as of 2026-07-28 (SEP-2577).", category=MCPDeprecationWarning)
async def log(self, level: LoggingLevel, data: Any, logger: str | None = None, *, meta: Meta | None = None) -> None:
"""Send a request-scoped `notifications/message` log entry.

View file

@ -4,6 +4,7 @@ from collections.abc import Iterable
from typing import TYPE_CHECKING, Any, Generic
from pydantic import AnyUrl, BaseModel
from typing_extensions import deprecated
from mcp.server.context import LifespanContextT, RequestT, ServerRequestContext
from mcp.server.elicitation import (
@ -14,6 +15,7 @@ from mcp.server.elicitation import (
elicit_with_validation,
)
from mcp.server.lowlevel.helper_types import ReadResourceContents
from mcp.shared.exceptions import MCPDeprecationWarning
from mcp.types import LoggingLevel
if TYPE_CHECKING:
@ -189,6 +191,7 @@ class Context(BaseModel, Generic[LifespanContextT, RequestT]):
related_request_id=self.request_id,
)
@deprecated("The logging capability is deprecated as of 2026-07-28 (SEP-2577).", category=MCPDeprecationWarning)
async def log(
self,
level: LoggingLevel,
@ -205,7 +208,7 @@ class Context(BaseModel, Generic[LifespanContextT, RequestT]):
(string, dict, list, number, bool, etc.) per the MCP specification.
logger_name: Optional logger name
"""
await self.request_context.session.send_log_message(
await self.request_context.session.send_log_message( # pyright: ignore[reportDeprecated]
level=level,
data=data,
logger=logger_name,
@ -265,18 +268,22 @@ class Context(BaseModel, Generic[LifespanContextT, RequestT]):
await self._request_context.close_standalone_sse_stream()
# Convenience methods for common log levels
@deprecated("The logging capability is deprecated as of 2026-07-28 (SEP-2577).", category=MCPDeprecationWarning)
async def debug(self, data: Any, *, logger_name: str | None = None) -> None:
"""Send a debug log message."""
await self.log("debug", data, logger_name=logger_name)
await self.log("debug", data, logger_name=logger_name) # pyright: ignore[reportDeprecated]
@deprecated("The logging capability is deprecated as of 2026-07-28 (SEP-2577).", category=MCPDeprecationWarning)
async def info(self, data: Any, *, logger_name: str | None = None) -> None:
"""Send an info log message."""
await self.log("info", data, logger_name=logger_name)
await self.log("info", data, logger_name=logger_name) # pyright: ignore[reportDeprecated]
@deprecated("The logging capability is deprecated as of 2026-07-28 (SEP-2577).", category=MCPDeprecationWarning)
async def warning(self, data: Any, *, logger_name: str | None = None) -> None:
"""Send a warning log message."""
await self.log("warning", data, logger_name=logger_name)
await self.log("warning", data, logger_name=logger_name) # pyright: ignore[reportDeprecated]
@deprecated("The logging capability is deprecated as of 2026-07-28 (SEP-2577).", category=MCPDeprecationWarning)
async def error(self, data: Any, *, logger_name: str | None = None) -> None:
"""Send an error log message."""
await self.log("error", data, logger_name=logger_name)
await self.log("error", data, logger_name=logger_name) # pyright: ignore[reportDeprecated]

View file

@ -12,12 +12,13 @@ used to live here are now owned by `JSONRPCDispatcher` and `ServerRunner`.
from typing import Any, TypeVar, cast, overload
from pydantic import AnyUrl, BaseModel
from typing_extensions import deprecated
from mcp import types
from mcp.server.connection import Connection
from mcp.server.validation import validate_sampling_tools, validate_tool_use_result_messages
from mcp.shared.dispatcher import CallOptions, Dispatcher, ProgressFnT
from mcp.shared.exceptions import NoBackChannelError, StatelessModeNotSupported
from mcp.shared.exceptions import MCPDeprecationWarning, NoBackChannelError, StatelessModeNotSupported
from mcp.shared.message import ServerMessageMetadata
from mcp.types import methods as _methods
@ -126,6 +127,7 @@ class ServerSession:
"""Check if the client supports a specific capability."""
return self._connection.check_capability(capability)
@deprecated("The logging capability is deprecated as of 2026-07-28 (SEP-2577).", category=MCPDeprecationWarning)
async def send_log_message(
self,
level: types.LoggingLevel,
@ -154,6 +156,7 @@ class ServerSession:
)
@overload
@deprecated("The sampling capability is deprecated as of 2026-07-28 (SEP-2577).", category=MCPDeprecationWarning)
async def create_message(
self,
messages: list[types.SamplingMessage],
@ -173,6 +176,7 @@ class ServerSession:
...
@overload
@deprecated("The sampling capability is deprecated as of 2026-07-28 (SEP-2577).", category=MCPDeprecationWarning)
async def create_message(
self,
messages: list[types.SamplingMessage],
@ -191,6 +195,7 @@ class ServerSession:
"""Overload: With tools, returns array-capable content."""
...
@deprecated("The sampling capability is deprecated as of 2026-07-28 (SEP-2577).", category=MCPDeprecationWarning)
async def create_message(
self,
messages: list[types.SamplingMessage],
@ -267,6 +272,7 @@ class ServerSession:
metadata=metadata_obj,
)
@deprecated("The roots capability is deprecated as of 2026-07-28 (SEP-2577).", category=MCPDeprecationWarning)
async def list_roots(self) -> types.ListRootsResult:
"""Send a roots/list request."""
if self._stateless:

View file

@ -5,6 +5,17 @@ from typing import Any, cast
from mcp.types import INVALID_REQUEST, URL_ELICITATION_REQUIRED, ElicitRequestURLParams, ErrorData, JSONRPCError
class MCPDeprecationWarning(UserWarning):
"""A custom deprecation warning for the MCP SDK.
Unlike the built-in `DeprecationWarning`, this inherits from `UserWarning` so
it is shown by default, helping users discover deprecated features without
enabling warnings explicitly.
Reference: https://sethmlarson.dev/deprecations-via-warnings-dont-work-for-python-libraries
"""
class MCPError(Exception):
"""Exception type raised when an error arrives over an MCP connection."""

View file

@ -13,8 +13,10 @@ from collections.abc import Mapping
from typing import Any, cast, overload
from pydantic import BaseModel
from typing_extensions import deprecated
from mcp.shared.dispatcher import CallOptions, Outbound
from mcp.shared.exceptions import MCPDeprecationWarning
from mcp.types import (
CreateMessageRequestParams,
CreateMessageResult,
@ -83,6 +85,7 @@ class ClientPeer:
await self._outbound.notify(method, params)
@overload
@deprecated("The sampling capability is deprecated as of 2026-07-28 (SEP-2577).", category=MCPDeprecationWarning)
async def sample(
self,
messages: list[SamplingMessage],
@ -100,6 +103,7 @@ class ClientPeer:
opts: CallOptions | None = None,
) -> CreateMessageResult: ...
@overload
@deprecated("The sampling capability is deprecated as of 2026-07-28 (SEP-2577).", category=MCPDeprecationWarning)
async def sample(
self,
messages: list[SamplingMessage],
@ -116,6 +120,7 @@ class ClientPeer:
meta: Meta | None = None,
opts: CallOptions | None = None,
) -> CreateMessageResultWithTools: ...
@deprecated("The sampling capability is deprecated as of 2026-07-28 (SEP-2577).", category=MCPDeprecationWarning)
async def sample(
self,
messages: list[SamplingMessage],
@ -195,6 +200,7 @@ class ClientPeer:
result = await self.send_raw_request("elicitation/create", dump_params(params, meta), opts)
return ElicitResult.model_validate(result, by_name=False)
@deprecated("The roots capability is deprecated as of 2026-07-28 (SEP-2577).", category=MCPDeprecationWarning)
async def list_roots(self, *, meta: Meta | None = None, opts: CallOptions | None = None) -> ListRootsResult:
"""Send a `roots/list` request.

View file

@ -259,7 +259,7 @@ async def test_client_unsubscribe_resource(simple_server: Server):
async def test_client_set_logging_level(simple_server: Server):
"""Test setting logging level."""
async with Client(simple_server) as client:
result = await client.set_logging_level("debug")
result = await client.set_logging_level("debug") # pyright: ignore[reportDeprecated]
assert result == snapshot(EmptyResult())

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