Drop Content and args parameter in ClientSessionGroup.call_tool (#1866)

Author: Kludex

docs/migration.md

@@ -52,6 +52,38 @@ async with http_client:
 
 The `headers`, `timeout`, `sse_read_timeout`, and `auth` parameters have been removed from `StreamableHTTPTransport`. Configure these on the `httpx.AsyncClient` instead (see example above).
 
+### `Content` type alias removed
+
+The deprecated `Content` type alias has been removed. Use `ContentBlock` directly instead.
+
+**Before (v1):**
+
+```python
+from mcp.types import Content
+```
+
+**After (v2):**
+
+```python
+from mcp.types import ContentBlock
+```
+
+### `args` parameter removed from `ClientSessionGroup.call_tool()`
+
+The deprecated `args` parameter has been removed from `ClientSessionGroup.call_tool()`. Use `arguments` instead.
+
+**Before (v1):**
+
+```python
+result = await session_group.call_tool("my_tool", args={"key": "value"})
+```
+
+**After (v2):**
+
+```python
+result = await session_group.call_tool("my_tool", arguments={"key": "value"})
+```
+
 ## Deprecations
 
 <!-- Add deprecations below -->

src/mcp/client/session_group.py

@@ -12,12 +12,12 @@
 from collections.abc import Callable
 from dataclasses import dataclass
 from types import TracebackType
-from typing import Any, TypeAlias, overload
+from typing import Any, TypeAlias
 
 import anyio
 import httpx
 from pydantic import BaseModel
-from typing_extensions import Self, deprecated
+from typing_extensions import Self
 
 import mcp
 from mcp import types
@@ -190,29 +190,6 @@ def tools(self) -> dict[str, types.Tool]:
         """Returns the tools as a dictionary of names to tools."""
         return self._tools
 
-    @overload
-    async def call_tool(
-        self,
-        name: str,
-        arguments: dict[str, Any],
-        read_timeout_seconds: float | None = None,
-        progress_callback: ProgressFnT | None = None,
-        *,
-        meta: dict[str, Any] | None = None,
-    ) -> types.CallToolResult: ...
-
-    @overload
-    @deprecated("The 'args' parameter is deprecated. Use 'arguments' instead.")
-    async def call_tool(
-        self,
-        name: str,
-        *,
-        args: dict[str, Any],
-        read_timeout_seconds: float | None = None,
-        progress_callback: ProgressFnT | None = None,
-        meta: dict[str, Any] | None = None,
-    ) -> types.CallToolResult: ...
-
     async def call_tool(
         self,
         name: str,
@@ -221,14 +198,13 @@ async def call_tool(
         progress_callback: ProgressFnT | None = None,
         *,
         meta: dict[str, Any] | None = None,
-        args: dict[str, Any] | None = None,
     ) -> types.CallToolResult:
         """Executes a tool given its name and arguments."""
         session = self._tool_to_session[name]
         session_tool_name = self.tools[name].name
         return await session.call_tool(
             session_tool_name,
-            arguments if args is None else args,
+            arguments=arguments,
             read_timeout_seconds=read_timeout_seconds,
             progress_callback=progress_callback,
             meta=meta,

src/mcp/types.py

@@ -1196,9 +1196,6 @@ class ResourceLink(Resource):
 ContentBlock = TextContent | ImageContent | AudioContent | ResourceLink | EmbeddedResource
 """A content block that can be used in prompts and tool results."""
 
-Content: TypeAlias = ContentBlock
-# """DEPRECATED: Content is deprecated, you should use ContentBlock directly."""
-
 
 class PromptMessage(BaseModel):
     """Describes a message returned as part of a prompt."""

tests/client/test_session_group.py

@@ -77,7 +77,7 @@ def hook(name: str, server_info: types.Implementation) -> str:  # pragma: no cov
         assert result.content == [text_content]
         mock_session.call_tool.assert_called_once_with(
             "my_tool",
-            {"name": "value1", "args": {}},
+            arguments={"name": "value1", "args": {}},
             read_timeout_seconds=None,
             progress_callback=None,
             meta=None,