Rename FastMCP to MCPServer (#1951)

tests/issues/test_100_tool_listing.py

@@ -1,12 +1,12 @@
 import pytest
 
-from mcp.server.fastmcp import FastMCP
+from mcp.server.mcpserver import MCPServer
 
 pytestmark = pytest.mark.anyio
 
 
 async def test_list_tools_returns_all_tools():
-    mcp = FastMCP("TestTools")
+    mcp = MCPServer("TestTools")
 
     # Create 100 tools with unique names
     num_tools = 100

tests/issues/test_1027_win_unreachable_cleanup.py

@@ -43,13 +43,13 @@ async def test_lifespan_cleanup_executed():
     Path(startup_marker).unlink()
     Path(cleanup_marker).unlink()
 
-    # Create a minimal MCP server using FastMCP that tracks lifecycle
+    # Create a minimal MCP server using MCPServer that tracks lifecycle
     server_code = textwrap.dedent(f"""
         import asyncio
         import sys
         from pathlib import Path
         from contextlib import asynccontextmanager
-        from mcp.server.fastmcp import FastMCP
+        from mcp.server.mcpserver import MCPServer
 
         STARTUP_MARKER = {escape_path_for_python(startup_marker)}
         CLEANUP_MARKER = {escape_path_for_python(cleanup_marker)}
@@ -64,7 +64,7 @@ async def test_lifespan_cleanup_executed():
                 # This cleanup code now runs properly during shutdown
                 Path(CLEANUP_MARKER).write_text("cleaned up")
 
-        mcp = FastMCP("test-server", lifespan=lifespan)
+        mcp = MCPServer("test-server", lifespan=lifespan)
 
         @mcp.tool()
         def echo(text: str) -> str:
@@ -156,7 +156,7 @@ async def test_stdin_close_triggers_cleanup():
         import sys
         from pathlib import Path
         from contextlib import asynccontextmanager
-        from mcp.server.fastmcp import FastMCP
+        from mcp.server.mcpserver import MCPServer
 
         STARTUP_MARKER = {escape_path_for_python(startup_marker)}
         CLEANUP_MARKER = {escape_path_for_python(cleanup_marker)}
@@ -171,7 +171,7 @@ async def test_stdin_close_triggers_cleanup():
                 # This cleanup code runs when stdin closes, enabling graceful shutdown
                 Path(CLEANUP_MARKER).write_text("cleaned up")
 
-        mcp = FastMCP("test-server", lifespan=lifespan)
+        mcp = MCPServer("test-server", lifespan=lifespan)
 
         @mcp.tool()
         def echo(text: str) -> str:

tests/issues/test_129_resource_templates.py

@@ -1,13 +1,13 @@
 import pytest
 
 from mcp import types
-from mcp.server.fastmcp import FastMCP
+from mcp.server.mcpserver import MCPServer
 
 
 @pytest.mark.anyio
 async def test_resource_templates():
     # Create an MCP server
-    mcp = FastMCP("Demo")
+    mcp = MCPServer("Demo")
 
     # Add a dynamic greeting resource
     @mcp.resource("greeting://{name}")
@@ -23,7 +23,7 @@ async def test_resource_templates():
     # Get the list of resource templates using the underlying server
     # Note: list_resource_templates() returns a decorator that wraps the handler
     # The handler returns a ServerResult with a ListResourceTemplatesResult inside
-    result = await mcp._mcp_server.request_handlers[types.ListResourceTemplatesRequest](
+    result = await mcp._lowlevel_server.request_handlers[types.ListResourceTemplatesRequest](
         types.ListResourceTemplatesRequest(params=None)
     )
     assert isinstance(result, types.ListResourceTemplatesResult)

tests/issues/test_1338_icons_and_metadata.py

@@ -2,7 +2,7 @@
 
 import pytest
 
-from mcp.server.fastmcp import FastMCP
+from mcp.server.mcpserver import MCPServer
 from mcp.types import Icon
 
 pytestmark = pytest.mark.anyio
@@ -19,7 +19,7 @@ async def test_icons_and_website_url():
     )
 
     # Create server with website URL and icon
-    mcp = FastMCP("TestServer", website_url="https://example.com", icons=[test_icon])
+    mcp = MCPServer("TestServer", website_url="https://example.com", icons=[test_icon])
 
     # Create tool with icon
     @mcp.tool(icons=[test_icon])
@@ -100,7 +100,7 @@ async def test_multiple_icons():
     icon2 = Icon(src="data:image/png;base64,icon2", mime_type="image/png", sizes=["32x32"])
     icon3 = Icon(src="data:image/png;base64,icon3", mime_type="image/png", sizes=["64x64"])
 
-    mcp = FastMCP("MultiIconServer")
+    mcp = MCPServer("MultiIconServer")
 
     # Create tool with multiple icons
     @mcp.tool(icons=[icon1, icon2, icon3])
@@ -122,7 +122,7 @@ async def test_multiple_icons():
 async def test_no_icons_or_website():
     """Test that server works without icons or websiteUrl."""
 
-    mcp = FastMCP("BasicServer")
+    mcp = MCPServer("BasicServer")
 
     @mcp.tool()
     def basic_tool() -> str:  # pragma: no cover

tests/issues/test_141_resource_templates.py

@@ -1,7 +1,7 @@
 import pytest
 
 from mcp import Client
-from mcp.server.fastmcp import FastMCP
+from mcp.server.mcpserver import MCPServer
 from mcp.types import (
     ListResourceTemplatesResult,
     TextResourceContents,
@@ -11,7 +11,7 @@ from mcp.types import (
 @pytest.mark.anyio
 async def test_resource_template_edge_cases():
     """Test server-side resource template validation"""
-    mcp = FastMCP("Demo")
+    mcp = MCPServer("Demo")
 
     # Test case 1: Template with multiple parameters
     @mcp.resource("resource://users/{user_id}/posts/{post_id}")
@@ -64,7 +64,7 @@ async def test_resource_template_edge_cases():
 @pytest.mark.anyio
 async def test_resource_template_client_interaction():
     """Test client-side resource template interaction"""
-    mcp = FastMCP("Demo")
+    mcp = MCPServer("Demo")
 
     # Register some templated resources
     @mcp.resource("resource://users/{user_id}/posts/{post_id}")

tests/issues/test_152_resource_mime_type.py

@@ -3,16 +3,16 @@ import base64
 import pytest
 
 from mcp import Client, types
-from mcp.server.fastmcp import FastMCP
 from mcp.server.lowlevel import Server
 from mcp.server.lowlevel.helper_types import ReadResourceContents
+from mcp.server.mcpserver import MCPServer
 
 pytestmark = pytest.mark.anyio
 
 
-async def test_fastmcp_resource_mime_type():
+async def test_mcpserver_resource_mime_type():
     """Test that mime_type parameter is respected for resources."""
-    mcp = FastMCP("test")
+    mcp = MCPServer("test")
 
     # Create a small test image as bytes
     image_bytes = b"fake_image_data"

tests/issues/test_1754_mime_type_parameters.py

@@ -7,14 +7,14 @@ with parameters like 'text/html;profile=mcp-app' which are valid per RFC 2045.
 import pytest
 
 from mcp import Client
-from mcp.server.fastmcp import FastMCP
+from mcp.server.mcpserver import MCPServer
 
 pytestmark = pytest.mark.anyio
 
 
 async def test_mime_type_with_parameters():
     """Test that MIME types with parameters are accepted (RFC 2045)."""
-    mcp = FastMCP("test")
+    mcp = MCPServer("test")
 
     # This should NOT raise a validation error
     @mcp.resource("ui://widget", mime_type="text/html;profile=mcp-app")
@@ -28,7 +28,7 @@ async def test_mime_type_with_parameters():
 
 async def test_mime_type_with_parameters_and_space():
     """Test MIME type with space after semicolon."""
-    mcp = FastMCP("test")
+    mcp = MCPServer("test")
 
     @mcp.resource("data://json", mime_type="application/json; charset=utf-8")
     def data() -> str:
@@ -41,7 +41,7 @@ async def test_mime_type_with_parameters_and_space():
 
 async def test_mime_type_with_multiple_parameters():
     """Test MIME type with multiple parameters."""
-    mcp = FastMCP("test")
+    mcp = MCPServer("test")
 
     @mcp.resource("data://multi", mime_type="text/plain; charset=utf-8; format=fixed")
     def data() -> str:
@@ -54,7 +54,7 @@ async def test_mime_type_with_multiple_parameters():
 
 async def test_mime_type_preserved_in_read_resource():
     """Test that MIME type with parameters is preserved when reading resource."""
-    mcp = FastMCP("test")
+    mcp = MCPServer("test")
 
     @mcp.resource("ui://my-widget", mime_type="text/html;profile=mcp-app")
     def my_widget() -> str:

tests/issues/test_176_progress_token.py

@@ -2,7 +2,7 @@ from unittest.mock import AsyncMock, MagicMock
 
 import pytest
 
-from mcp.server.fastmcp import Context
+from mcp.server.mcpserver import Context
 from mcp.shared.context import RequestContext
 
 pytestmark = pytest.mark.anyio
@@ -24,7 +24,7 @@ async def test_progress_token_zero_first_call():
     )
 
     # Create context with our mocks
-    ctx = Context(request_context=request_context, fastmcp=MagicMock())
+    ctx = Context(request_context=request_context, mcp_server=MagicMock())
 
     # Test progress reporting
     await ctx.report_progress(0, 10)  # First call with 0

tests/issues/test_188_concurrency.py

@@ -2,12 +2,12 @@ import anyio
 import pytest
 
 from mcp import Client
-from mcp.server.fastmcp import FastMCP
+from mcp.server.mcpserver import MCPServer
 
 
 @pytest.mark.anyio
 async def test_messages_are_executed_concurrently_tools():
-    server = FastMCP("test")
+    server = MCPServer("test")
     event = anyio.Event()
     tool_started = anyio.Event()
     call_order: list[str] = []
@@ -48,7 +48,7 @@ async def test_messages_are_executed_concurrently_tools():
 
 @pytest.mark.anyio
 async def test_messages_are_executed_concurrently_tools_and_resources():
-    server = FastMCP("test")
+    server = MCPServer("test")
     event = anyio.Event()
     tool_started = anyio.Event()
     call_order: list[str] = []

tests/issues/test_355_type_error.py

@@ -2,7 +2,7 @@ from collections.abc import AsyncIterator
 from contextlib import asynccontextmanager
 from dataclasses import dataclass
 
-from mcp.server.fastmcp import Context, FastMCP
+from mcp.server.mcpserver import Context, MCPServer
 from mcp.server.session import ServerSession
 
 
@@ -19,7 +19,7 @@ class Database:  # Replace with your actual DB type
 
 
 # Create a named server
-mcp = FastMCP("My App")
+mcp = MCPServer("My App")
 
 
 @dataclass
@@ -28,7 +28,7 @@ class AppContext:
 
 
 @asynccontextmanager
-async def app_lifespan(server: FastMCP) -> AsyncIterator[AppContext]:  # pragma: no cover
+async def app_lifespan(server: MCPServer) -> AsyncIterator[AppContext]:  # pragma: no cover
     """Manage application lifecycle with type-safe context"""
     # Initialize on startup
     db = await Database.connect()
@@ -40,7 +40,7 @@ async def app_lifespan(server: FastMCP) -> AsyncIterator[AppContext]:  # pragma:
 
 
 # Pass lifespan to server
-mcp = FastMCP("My App", lifespan=app_lifespan)
+mcp = MCPServer("My App", lifespan=app_lifespan)
 
 
 # Access type-safe lifespan context in tools

tests/issues/test_973_url_decoding.py

@@ -3,7 +3,7 @@
 Regression test for https://github.com/modelcontextprotocol/python-sdk/issues/973
 """
 
-from mcp.server.fastmcp.resources import ResourceTemplate
+from mcp.server.mcpserver.resources import ResourceTemplate
 
 
 def test_template_matches_decodes_space():