Merge branch 'main' into docs

src/fastmcp/server/openapi.py

@@ -115,6 +115,7 @@ class OpenAPITool(Tool):
         parameters: dict[str, Any],
         fn_metadata: Any,
         is_async: bool = True,
+        tags: set[str] = set(),
     ):
         super().__init__(
             name=name,
@@ -124,6 +125,7 @@ class OpenAPITool(Tool):
             fn_metadata=fn_metadata,
             is_async=is_async,
             context_kwarg="context",  # Default context keyword argument
+            tags=tags,
         )
         self._client = client
         self._route = route
@@ -242,12 +244,14 @@ class OpenAPIResource(Resource):
         name: str,
         description: str,
         mime_type: str = "application/json",
+        tags: set[str] = set(),
     ):
         super().__init__(
             uri=AnyUrl(uri),  # Convert string to AnyUrl
             name=name,
             description=description,
             mime_type=mime_type,
+            tags=tags,
         )
         self._client = client
         self._route = route
@@ -332,6 +336,7 @@ class OpenAPIResourceTemplate(ResourceTemplate):
         name: str,
         description: str,
         parameters: dict[str, Any],
+        tags: set[str] = set(),
     ):
         super().__init__(
             uri_template=uri_template,
@@ -339,6 +344,7 @@ class OpenAPIResourceTemplate(ResourceTemplate):
             description=description,
             fn=self._create_resource_fn,
             parameters=parameters,
+            tags=tags,
         )
         self._client = client
         self._route = route
@@ -405,6 +411,7 @@ class OpenAPIResourceTemplate(ResourceTemplate):
             description=self.description
             or f"Resource for {self._route.path}",  # Provide default if None
             mime_type="application/json",  # Default, will be updated when read
+            tags=set(self._route.tags or []),
         )
 
 
@@ -525,10 +532,13 @@ class FastMCPOpenAPI(FastMCP):
             parameters=combined_schema,
             fn_metadata=func_metadata(_openapi_passthrough),
             is_async=True,
+            tags=set(route.tags or []),
         )
         # Register the tool by directly assigning to the tools dictionary
         self._tool_manager._tools[tool_name] = tool
-        logger.debug(f"Registered TOOL: {tool_name} ({route.method} {route.path})")
+        logger.debug(
+            f"Registered TOOL: {tool_name} ({route.method} {route.path}) with tags: {route.tags}"
+        )
 
     def _create_openapi_resource(self, route: openapi.HTTPRoute, operation_id: str):
         """Creates and registers an OpenAPIResource with enhanced description."""
@@ -550,11 +560,12 @@ class FastMCPOpenAPI(FastMCP):
             uri=resource_uri,
             name=resource_name,
             description=enhanced_description,
+            tags=set(route.tags or []),
         )
         # Register the resource by directly assigning to the resources dictionary
         self._resource_manager._resources[str(resource.uri)] = resource
         logger.debug(
-            f"Registered RESOURCE: {resource_uri} ({route.method} {route.path})"
+            f"Registered RESOURCE: {resource_uri} ({route.method} {route.path}) with tags: {route.tags}"
         )
 
     def _create_openapi_template(self, route: openapi.HTTPRoute, operation_id: str):
@@ -594,11 +605,12 @@ class FastMCPOpenAPI(FastMCP):
             name=template_name,
             description=enhanced_description,
             parameters=template_params_schema,
+            tags=set(route.tags or []),
         )
         # Register the template by directly assigning to the templates dictionary
         self._resource_manager._templates[uri_template_str] = template
         logger.debug(
-            f"Registered TEMPLATE: {uri_template_str} ({route.method} {route.path})"
+            f"Registered TEMPLATE: {uri_template_str} ({route.method} {route.path}) with tags: {route.tags}"
         )
 
     async def call_tool(self, name: str, arguments: dict[str, Any]) -> Any:

src/fastmcp/server/server.py

@@ -3,7 +3,7 @@
 import inspect
 import json
 import re
-from collections.abc import AsyncIterator, Callable, Sequence
+from collections.abc import AsyncIterator, Callable
 from contextlib import (
     AbstractAsyncContextManager,
     asynccontextmanager,
@@ -78,8 +78,10 @@ class FastMCP(Generic[LifespanResultT]):
         lifespan: (
             Callable[["FastMCP"], AbstractAsyncContextManager[LifespanResultT]] | None
         ) = None,
+        tags: set[str] | None = None,
         **settings: Any,
     ):
+        self.tags: set[str] = tags or set()
         self.settings = fastmcp.settings.ServerSettings(**settings)
 
         self._mcp_server = MCPServer[LifespanResultT](
@@ -178,7 +180,7 @@ class FastMCP(Generic[LifespanResultT]):
 
     async def call_tool(
         self, name: str, arguments: dict[str, Any]
-    ) -> Sequence[TextContent | ImageContent | EmbeddedResource]:
+    ) -> list[TextContent | ImageContent | EmbeddedResource]:
         """Call a tool by name with arguments."""
         context = self.get_context()
         result = await self._tool_manager.call_tool(name, arguments, context=context)

tests/server/test_openapi.py

@@ -36,17 +36,17 @@ def users_db() -> dict[int, User]:
 def fastapi_app(users_db: dict[int, User]) -> FastAPI:
     app = FastAPI(title="FastAPI App")
 
-    @app.get("/users")
+    @app.get("/users", tags=["users", "list"])
     async def get_users() -> list[User]:
         """Get all users."""
         return sorted(users_db.values(), key=lambda x: x.id)
 
-    @app.get("/users/{user_id}")
+    @app.get("/users/{user_id}", tags=["users", "detail"])
     async def get_user(user_id: int) -> User | None:
         """Get a user by ID."""
         return users_db.get(user_id)
 
-    @app.post("/users")
+    @app.post("/users", tags=["users", "create"])
     async def create_user(user: UserCreate) -> User:
         """Create a new user."""
         user_id = max(users_db.keys()) + 1
@@ -54,7 +54,7 @@ def fastapi_app(users_db: dict[int, User]) -> FastAPI:
         users_db[user_id] = new_user
         return new_user
 
-    @app.patch("/users/{user_id}/name")
+    @app.patch("/users/{user_id}/name", tags=["users", "update"])
     async def update_user_name(user_id: int, name: str) -> User:
         """Update a user's name."""
         user = users_db.get(user_id)
@@ -258,3 +258,98 @@ class TestPrompts:
         """
         prompts = await fastmcp_server.list_prompts()
         assert len(prompts) == 0
+
+
+class TestTagTransfer:
+    """Tests for transferring tags from OpenAPI to MCP objects."""
+
+    async def test_tags_transferred_to_tools(self, fastmcp_server: FastMCPOpenAPI):
+        """Test that tags from OpenAPI routes are correctly transferred to Tools."""
+        # Get internal tools directly (not the public API which returns MCP.Content)
+        tools = fastmcp_server._tool_manager.list_tools()
+
+        # Find the create_user and update_user_name tools
+        create_user_tool = next(
+            (t for t in tools if t.name == "create_user_users_post"), None
+        )
+        update_user_tool = next(
+            (
+                t
+                for t in tools
+                if t.name == "update_user_name_users__user_id__name_patch"
+            ),
+            None,
+        )
+
+        assert create_user_tool is not None
+        assert update_user_tool is not None
+
+        # Check that tags from OpenAPI routes were transferred to the Tool objects
+        assert "users" in create_user_tool.tags
+        assert "create" in create_user_tool.tags
+        assert len(create_user_tool.tags) == 2
+
+        assert "users" in update_user_tool.tags
+        assert "update" in update_user_tool.tags
+        assert len(update_user_tool.tags) == 2
+
+    async def test_tags_transferred_to_resources(self, fastmcp_server: FastMCPOpenAPI):
+        """Test that tags from OpenAPI routes are correctly transferred to Resources."""
+        # Get internal resources directly
+        resources = fastmcp_server._resource_manager.list_resources()
+
+        # Find the get_users resource
+        get_users_resource = next(
+            (r for r in resources if r.name == "get_users_users_get"), None
+        )
+
+        assert get_users_resource is not None
+
+        # Check that tags from OpenAPI routes were transferred to the Resource object
+        assert "users" in get_users_resource.tags
+        assert "list" in get_users_resource.tags
+        assert len(get_users_resource.tags) == 2
+
+    async def test_tags_transferred_to_resource_templates(
+        self, fastmcp_server: FastMCPOpenAPI
+    ):
+        """Test that tags from OpenAPI routes are correctly transferred to ResourceTemplates."""
+        # Get internal resource templates directly
+        templates = fastmcp_server._resource_manager.list_templates()
+
+        # Find the get_user template
+        get_user_template = next(
+            (t for t in templates if t.name == "get_user_users__user_id__get"), None
+        )
+
+        assert get_user_template is not None
+
+        # Check that tags from OpenAPI routes were transferred to the ResourceTemplate object
+        assert "users" in get_user_template.tags
+        assert "detail" in get_user_template.tags
+        assert len(get_user_template.tags) == 2
+
+    async def test_tags_preserved_in_resources_created_from_templates(
+        self, fastmcp_server: FastMCPOpenAPI
+    ):
+        """Test that tags are preserved when creating resources from templates."""
+        # Get internal resource templates directly
+        templates = fastmcp_server._resource_manager.list_templates()
+
+        # Find the get_user template
+        get_user_template = next(
+            (t for t in templates if t.name == "get_user_users__user_id__get"), None
+        )
+
+        assert get_user_template is not None
+
+        # Manually create a resource from template
+        params = {"user_id": 1}
+        resource = await get_user_template.create_resource(
+            "resource://openapi/get_user_users__user_id__get/1", params
+        )
+
+        # Verify tags are preserved from template to resource
+        assert "users" in resource.tags
+        assert "detail" in resource.tags
+        assert len(resource.tags) == 2

tests/server/test_server.py

@@ -5,9 +5,6 @@ from typing import TYPE_CHECKING
 
 import pytest
 from mcp.shared.exceptions import McpError
-from mcp.shared.memory import (
-    create_connected_server_and_client_session as client_session,
-)
 from mcp.types import (
     BlobResourceContents,
     ImageContent,
@@ -16,7 +13,8 @@ from mcp.types import (
 )
 from pydantic import AnyUrl, Field
 
-from fastmcp import Context, FastMCP
+from fastmcp import Client, Context, FastMCP
+from fastmcp.exceptions import ToolError
 from fastmcp.prompts.prompt import EmbeddedResource, Message, UserMessage
 from fastmcp.resources import FileResource, FunctionResource
 from fastmcp.utilities.types import Image
@@ -25,7 +23,7 @@ if TYPE_CHECKING:
     from fastmcp import Context
 
 
-class TestServer:
+class TestCreateServer:
     async def test_create_server(self):
         mcp = FastMCP(instructions="Server instructions")
         assert mcp.name == "FastMCP"
@@ -43,18 +41,18 @@ class TestServer:
         def hello_world(name: str = "世界") -> str:
             return f"¡Hola, {name}! 👋"
 
-        async with client_session(mcp._mcp_server) as client:
+        async with Client(mcp) as client:
             tools = await client.list_tools()
-            assert len(tools.tools) == 1
-            tool = tools.tools[0]
+            assert len(tools) == 1
+            tool = tools[0]
             assert tool.description is not None
             assert "🌟" in tool.description
             assert "漢字" in tool.description
             assert "🎉" in tool.description
 
             result = await client.call_tool("hello_world", {})
-            assert len(result.content) == 1
-            content = result.content[0]
+            assert len(result) == 1
+            content = result[0]
             assert isinstance(content, TextContent)
             assert "¡Hola, 世界! 👋" == content.text
 
@@ -97,171 +95,135 @@ class TestServer:
                 return f"Data: {x}"
 
 
-def tool_fn(x: int, y: int) -> int:
-    return x + y
-
+@pytest.fixture
+def tool_server():
+    mcp = FastMCP()
 
-def tool_fn_list() -> list[str | int]:
-    return ["x", 2]
+    @mcp.tool()
+    def add(x: int, y: int) -> int:
+        return x + y
 
+    @mcp.tool()
+    def list_tool() -> list[str | int]:
+        return ["x", 2]
 
-def error_tool_fn() -> None:
-    raise ValueError("Test error")
+    @mcp.tool()
+    def error_tool() -> None:
+        raise ValueError("Test error")
 
+    @mcp.tool()
+    def image_tool(path: str) -> Image:
+        return Image(path)
 
-def image_tool_fn(path: str) -> Image:
-    return Image(path)
+    @mcp.tool()
+    def mixed_content_tool() -> list[TextContent | ImageContent]:
+        return [
+            TextContent(type="text", text="Hello"),
+            ImageContent(type="image", data="abc", mimeType="image/png"),
+        ]
 
+    @mcp.tool()
+    def mixed_list_fn(image_path: str) -> list:
+        return [
+            "text message",
+            Image(image_path),
+            {"key": "value"},
+            TextContent(type="text", text="direct content"),
+        ]
 
-def mixed_content_tool_fn() -> list[TextContent | ImageContent]:
-    return [
-        TextContent(type="text", text="Hello"),
-        ImageContent(type="image", data="abc", mimeType="image/png"),
-    ]
+    return mcp
 
 
 class TestServerTools:
-    async def test_add_tool(self):
-        mcp = FastMCP()
-        mcp.add_tool(tool_fn)
-        mcp.add_tool(tool_fn)
-        assert len(mcp._tool_manager.list_tools()) == 1
-
-    async def test_list_tools(self):
-        mcp = FastMCP()
-        mcp.add_tool(tool_fn)
-        async with client_session(mcp._mcp_server) as client:
-            tools = await client.list_tools()
-            assert len(tools.tools) == 1
-
-    async def test_call_tool(self):
-        mcp = FastMCP()
-        mcp.add_tool(tool_fn)
-        async with client_session(mcp._mcp_server) as client:
-            result = await client.call_tool("my_tool", {"arg1": "value"})
-            assert not hasattr(result, "error")
-            assert len(result.content) > 0
-
-    async def test_tool_exception_handling(self):
-        mcp = FastMCP()
-        mcp.add_tool(error_tool_fn)
-        async with client_session(mcp._mcp_server) as client:
-            result = await client.call_tool("error_tool_fn", {})
-            assert len(result.content) == 1
-            content = result.content[0]
-            assert isinstance(content, TextContent)
-            assert "Test error" in content.text
-            assert result.isError is True
-
-    async def test_tool_error_handling(self):
-        mcp = FastMCP()
-        mcp.add_tool(error_tool_fn)
-        async with client_session(mcp._mcp_server) as client:
-            result = await client.call_tool("error_tool_fn", {})
-            assert len(result.content) == 1
-            content = result.content[0]
-            assert isinstance(content, TextContent)
-            assert "Test error" in content.text
-            assert result.isError is True
-
-    async def test_tool_error_details(self):
-        """Test that exception details are properly formatted in the response"""
-        mcp = FastMCP()
-        mcp.add_tool(error_tool_fn)
-        async with client_session(mcp._mcp_server) as client:
-            result = await client.call_tool("error_tool_fn", {})
-            content = result.content[0]
-            assert isinstance(content, TextContent)
-            assert isinstance(content.text, str)
-            assert "Test error" in content.text
-            assert result.isError is True
-
-    async def test_tool_return_value_conversion(self):
-        mcp = FastMCP()
-        mcp.add_tool(tool_fn)
-        async with client_session(mcp._mcp_server) as client:
-            result = await client.call_tool("tool_fn", {"x": 1, "y": 2})
-            assert len(result.content) == 1
-            content = result.content[0]
-            assert isinstance(content, TextContent)
-            assert content.text == "3"
-
-    async def test_tool_returns_list(self):
-        mcp = FastMCP()
-        mcp.add_tool(tool_fn_list)
-        async with client_session(mcp._mcp_server) as client:
-            result = await client.call_tool("tool_fn_list", {})
-            assert len(result.content) == 1
-            content = result.content[0]
-            assert isinstance(content, TextContent)
-            assert json.loads(content.text) == ["x", 2]
-
-    async def test_tool_image_helper(self, tmp_path: Path):
+    async def test_add_tool_exists(self, tool_server: FastMCP):
+        assert "add" in [t.name for t in await tool_server.list_tools()]
+
+    async def test_list_tools(self, tool_server: FastMCP):
+        assert len(await tool_server.list_tools()) == 6
+
+    async def test_call_tool(self, tool_server: FastMCP):
+        result = await tool_server.call_tool("add", {"x": 1, "y": 2})
+        assert isinstance(result[0], TextContent)
+        assert result[0].text == "3"
+
+    async def test_call_tool_as_client(self, tool_server: FastMCP):
+        async with Client(tool_server) as client:
+            result = await client.call_tool("add", {"x": 1, "y": 2})
+            assert isinstance(result[0], TextContent)
+            assert result[0].text == "3"
+
+    async def test_call_tool_error(self, tool_server: FastMCP):
+        with pytest.raises(ToolError):
+            await tool_server.call_tool("error_tool", {})
+
+    async def test_call_tool_error_as_client(self, tool_server: FastMCP):
+        async with Client(tool_server) as client:
+            with pytest.raises(Exception):
+                await client.call_tool("error_tool", {})
+
+    async def test_call_tool_error_as_client_raw(self, tool_server: FastMCP):
+        async with Client(tool_server) as client:
+            result = await client.call_tool("error_tool", {}, _return_raw_result=True)
+        assert result.isError
+        assert isinstance(result.content[0], TextContent)
+        assert "Test error" in result.content[0].text
+
+    async def test_tool_returns_list(self, tool_server: FastMCP):
+        result = await tool_server.call_tool("list_tool", {})
+        assert isinstance(result[0], TextContent)
+        assert result[0].text == '["x", 2]'
+
+    async def test_tool_image_helper(self, tool_server: FastMCP, tmp_path: Path):
         # Create a test image
         image_path = tmp_path / "test.png"
         image_path.write_bytes(b"fake png data")
 
-        mcp = FastMCP()
-        mcp.add_tool(image_tool_fn)
-        async with client_session(mcp._mcp_server) as client:
-            result = await client.call_tool("image_tool_fn", {"path": str(image_path)})
-            assert len(result.content) == 1
-            content = result.content[0]
-            assert isinstance(content, ImageContent)
-            assert content.type == "image"
-            assert content.mimeType == "image/png"
-            # Verify base64 encoding
-            decoded = base64.b64decode(content.data)
-            assert decoded == b"fake png data"
-
-    async def test_tool_mixed_content(self):
-        mcp = FastMCP()
-        mcp.add_tool(mixed_content_tool_fn)
-        async with client_session(mcp._mcp_server) as client:
-            result = await client.call_tool("mixed_content_tool_fn", {})
-
-            assert len(result.content) == 2
-            content1 = result.content[0]
-            content2 = result.content[1]
-            assert isinstance(content1, TextContent)
-            assert content1.text == "Hello"
-            assert isinstance(content2, ImageContent)
-            assert content2.mimeType == "image/png"
-            assert content2.data == "abc"
-
-    async def test_tool_mixed_list_with_image(self, tmp_path: Path):
+        result = await tool_server.call_tool("image_tool", {"path": str(image_path)})
+        content = result[0]
+        assert isinstance(content, ImageContent)
+        assert content.type == "image"
+        assert content.mimeType == "image/png"
+        # Verify base64 encoding
+        decoded = base64.b64decode(content.data)
+        assert decoded == b"fake png data"
+
+    async def test_tool_mixed_content(self, tool_server: FastMCP):
+        result = await tool_server.call_tool("mixed_content_tool", {})
+        assert len(result) == 2
+        content1 = result[0]
+        content2 = result[1]
+        assert isinstance(content1, TextContent)
+        assert content1.text == "Hello"
+        assert isinstance(content2, ImageContent)
+        assert content2.mimeType == "image/png"
+        assert content2.data == "abc"
+
+    async def test_tool_mixed_list_with_image(
+        self, tool_server: FastMCP, tmp_path: Path
+    ):
         """Test that lists containing Image objects and other types are handled
         correctly. Note that the non-MCP content will be grouped together."""
         # Create a test image
         image_path = tmp_path / "test.png"
         image_path.write_bytes(b"test image data")
 
-        def mixed_list_fn() -> list:
-            return [
-                "text message",
-                Image(image_path),
-                {"key": "value"},
-                TextContent(type="text", text="direct content"),
-            ]
-
-        mcp = FastMCP()
-        mcp.add_tool(mixed_list_fn)
-        async with client_session(mcp._mcp_server) as client:
-            result = await client.call_tool("mixed_list_fn", {})
-            assert len(result.content) == 3
-            # Check text conversion
-            content1 = result.content[0]
-            assert isinstance(content1, TextContent)
-            assert json.loads(content1.text) == ["text message", {"key": "value"}]
-            # Check image conversion
-            content2 = result.content[1]
-            assert isinstance(content2, ImageContent)
-            assert content2.mimeType == "image/png"
-            assert base64.b64decode(content2.data) == b"test image data"
-            # Check direct TextContent
-            content3 = result.content[2]
-            assert isinstance(content3, TextContent)
-            assert content3.text == "direct content"
+        result = await tool_server.call_tool(
+            "mixed_list_fn", {"image_path": str(image_path)}
+        )
+        assert len(result) == 3
+        # Check text conversion
+        content1 = result[0]
+        assert isinstance(content1, TextContent)
+        assert json.loads(content1.text) == ["text message", {"key": "value"}]
+        # Check image conversion
+        content2 = result[1]
+        assert isinstance(content2, ImageContent)
+        assert content2.mimeType == "image/png"
+        assert base64.b64decode(content2.data) == b"test image data"
+        # Check direct TextContent
+        content3 = result[2]
+        assert isinstance(content3, TextContent)
+        assert content3.text == "direct content"
 
     async def test_parameter_descriptions(self):
         mcp = FastMCP("Test Server")
@@ -298,10 +260,10 @@ class TestServerResources:
         )
         mcp.add_resource(resource)
 
-        async with client_session(mcp._mcp_server) as client:
+        async with Client(mcp) as client:
             result = await client.read_resource(AnyUrl("resource://test"))
-            assert isinstance(result.contents[0], TextResourceContents)
-            assert result.contents[0].text == "Hello, world!"
+            assert isinstance(result[0], TextResourceContents)
+            assert result[0].text == "Hello, world!"
 
     async def test_binary_resource(self):
         mcp = FastMCP()
@@ -317,10 +279,10 @@ class TestServerResources:
         )
         mcp.add_resource(resource)
 
-        async with client_session(mcp._mcp_server) as client:
+        async with Client(mcp) as client:
             result = await client.read_resource(AnyUrl("resource://binary"))
-            assert isinstance(result.contents[0], BlobResourceContents)
-            assert result.contents[0].blob == base64.b64encode(b"Binary data").decode()
+            assert isinstance(result[0], BlobResourceContents)
+            assert result[0].blob == base64.b64encode(b"Binary data").decode()
 
     async def test_file_resource_text(self, tmp_path: Path):
         mcp = FastMCP()
@@ -334,10 +296,10 @@ class TestServerResources:
         )
         mcp.add_resource(resource)
 
-        async with client_session(mcp._mcp_server) as client:
+        async with Client(mcp) as client:
             result = await client.read_resource(AnyUrl("file://test.txt"))
-            assert isinstance(result.contents[0], TextResourceContents)
-            assert result.contents[0].text == "Hello from file!"
+            assert isinstance(result[0], TextResourceContents)
+            assert result[0].text == "Hello from file!"
 
     async def test_file_resource_binary(self, tmp_path: Path):
         mcp = FastMCP()
@@ -354,13 +316,10 @@ class TestServerResources:
         )
         mcp.add_resource(resource)
 
-        async with client_session(mcp._mcp_server) as client:
+        async with Client(mcp) as client:
             result = await client.read_resource(AnyUrl("file://test.bin"))
-            assert isinstance(result.contents[0], BlobResourceContents)
-            assert (
-                result.contents[0].blob
-                == base64.b64encode(b"Binary file data").decode()
-            )
+            assert isinstance(result[0], BlobResourceContents)
+            assert result[0].blob == base64.b64encode(b"Binary file data").decode()
 
 
 class TestServerResourceTemplates:
@@ -401,10 +360,10 @@ class TestServerResourceTemplates:
         def get_data(name: str) -> str:
             return f"Data for {name}"
 
-        async with client_session(mcp._mcp_server) as client:
+        async with Client(mcp) as client:
             result = await client.read_resource(AnyUrl("resource://test/data"))
-            assert isinstance(result.contents[0], TextResourceContents)
-            assert result.contents[0].text == "Data for test"
+            assert isinstance(result[0], TextResourceContents)
+            assert result[0].text == "Data for test"
 
     async def test_resource_mismatched_params(self):
         """Test that mismatched parameters raise an error"""
@@ -424,12 +383,12 @@ class TestServerResourceTemplates:
         def get_data(org: str, repo: str) -> str:
             return f"Data for {org}/{repo}"
 
-        async with client_session(mcp._mcp_server) as client:
+        async with Client(mcp) as client:
             result = await client.read_resource(
                 AnyUrl("resource://cursor/fastmcp/data")
             )
-            assert isinstance(result.contents[0], TextResourceContents)
-            assert result.contents[0].text == "Data for cursor/fastmcp"
+            assert isinstance(result[0], TextResourceContents)
+            assert result[0].text == "Data for cursor/fastmcp"
 
     async def test_resource_multiple_mismatched_params(self):
         """Test that mismatched parameters raise an error"""
@@ -448,10 +407,10 @@ class TestServerResourceTemplates:
         def get_static_data() -> str:
             return "Static data"
 
-        async with client_session(mcp._mcp_server) as client:
+        async with Client(mcp) as client:
             result = await client.read_resource(AnyUrl("resource://static"))
-            assert isinstance(result.contents[0], TextResourceContents)
-            assert result.contents[0].text == "Static data"
+            assert isinstance(result[0], TextResourceContents)
+            assert result[0].text == "Static data"
 
     async def test_template_to_resource_conversion(self):
         """Test that templates are properly converted to resources when accessed"""
@@ -494,10 +453,10 @@ class TestContextInjection:
             return f"Request {ctx.request_id}: {x}"
 
         mcp.add_tool(tool_with_context)
-        async with client_session(mcp._mcp_server) as client:
+        async with Client(mcp) as client:
             result = await client.call_tool("tool_with_context", {"x": 42})
-            assert len(result.content) == 1
-            content = result.content[0]
+            assert len(result) == 1
+            content = result[0]
             assert isinstance(content, TextContent)
             assert "Request" in content.text
             assert "42" in content.text
@@ -511,10 +470,10 @@ class TestContextInjection:
             return f"Async request {ctx.request_id}: {x}"
 
         mcp.add_tool(async_tool)
-        async with client_session(mcp._mcp_server) as client:
+        async with Client(mcp) as client:
             result = await client.call_tool("async_tool", {"x": 42})
-            assert len(result.content) == 1
-            content = result.content[0]
+            assert len(result) == 1
+            content = result[0]
             assert isinstance(content, TextContent)
             assert "Async request" in content.text
             assert "42" in content.text
@@ -537,10 +496,10 @@ class TestContextInjection:
         mcp.add_tool(logging_tool)
 
         with patch("mcp.server.session.ServerSession.send_log_message") as mock_log:
-            async with client_session(mcp._mcp_server) as client:
+            async with Client(mcp) as client:
                 result = await client.call_tool("logging_tool", {"msg": "test"})
-                assert len(result.content) == 1
-                content = result.content[0]
+                assert len(result) == 1
+                content = result[0]
                 assert isinstance(content, TextContent)
                 assert "Logged messages for test" in content.text
 
@@ -564,10 +523,10 @@ class TestContextInjection:
             return x * 2
 
         mcp.add_tool(no_context)
-        async with client_session(mcp._mcp_server) as client:
+        async with Client(mcp) as client:
             result = await client.call_tool("no_context", {"x": 21})
-            assert len(result.content) == 1
-            content = result.content[0]
+            assert len(result) == 1
+            content = result[0]
             assert isinstance(content, TextContent)
             assert content.text == "42"
 
@@ -587,10 +546,10 @@ class TestContextInjection:
             r = r_list[0]
             return f"Read resource: {r.content} with mime type {r.mime_type}"
 
-        async with client_session(mcp._mcp_server) as client:
+        async with Client(mcp) as client:
             result = await client.call_tool("tool_with_resource", {})
-            assert len(result.content) == 1
-            content = result.content[0]
+            assert len(result) == 1
+            content = result[0]
             assert isinstance(content, TextContent)
             assert "Read resource: resource data" in content.text
 
@@ -661,11 +620,11 @@ class TestServerPrompts:
         def fn(name: str, optional: str = "default") -> str:
             return f"Hello, {name}!"
 
-        async with client_session(mcp._mcp_server) as client:
+        async with Client(mcp) as client:
             result = await client.list_prompts()
-            assert result.prompts is not None
-            assert len(result.prompts) == 1
-            prompt = result.prompts[0]
+            assert result is not None
+            assert len(result) == 1
+            prompt = result[0]
             assert prompt.name == "fn"
             assert prompt.arguments is not None
             assert len(prompt.arguments) == 2
@@ -682,7 +641,7 @@ class TestServerPrompts:
         def fn(name: str) -> str:
             return f"Hello, {name}!"
 
-        async with client_session(mcp._mcp_server) as client:
+        async with Client(mcp) as client:
             result = await client.get_prompt("fn", {"name": "World"})
             assert len(result.messages) == 1
             message = result.messages[0]
@@ -708,12 +667,10 @@ class TestServerPrompts:
                 )
             )
 
-        async with client_session(mcp._mcp_server) as client:
+        async with Client(mcp) as client:
             result = await client.get_prompt("fn")
-            assert len(result.messages) == 1
-            message = result.messages[0]
-            assert message.role == "user"
-            content = message.content
+            assert result.messages[0].role == "user"
+            content = result.messages[0].content
             assert isinstance(content, EmbeddedResource)
             resource = content.resource
             assert isinstance(resource, TextResourceContents)
@@ -723,7 +680,7 @@ class TestServerPrompts:
     async def test_get_unknown_prompt(self):
         """Test error when getting unknown prompt."""
         mcp = FastMCP()
-        async with client_session(mcp._mcp_server) as client:
+        async with Client(mcp) as client:
             with pytest.raises(McpError, match="Unknown prompt"):
                 await client.get_prompt("unknown")
 
@@ -735,7 +692,7 @@ class TestServerPrompts:
         def prompt_fn(name: str) -> str:
             return f"Hello, {name}!"
 
-        async with client_session(mcp._mcp_server) as client:
+        async with Client(mcp) as client:
             with pytest.raises(McpError, match="Missing required arguments"):
                 await client.get_prompt("prompt_fn")
 

tests/utilities/openapi/test_openapi.py

@@ -460,6 +460,63 @@ def test_petstore_required_fields_resolution(parsed_petstore_routes):
     assert json_schema.get("required") == ["id", "name"]
 
 
+def test_tags_parsing_in_petstore_routes(parsed_petstore_routes):
+    """Test that tags are correctly parsed from the OpenAPI schema."""
+    # All petstore routes should have the "pets" tag
+    for route in parsed_petstore_routes:
+        assert "pets" in route.tags, (
+            f"Route {route.method} {route.path} is missing 'pets' tag"
+        )
+
+
+def test_tag_list_structure(parsed_petstore_routes):
+    """Test that tags are stored as a list of strings."""
+    for route in parsed_petstore_routes:
+        assert isinstance(route.tags, list), "Tags should be stored as a list"
+        for tag in route.tags:
+            assert isinstance(tag, str), "Each tag should be a string"
+
+
+def test_empty_tags_handling(bookstore_schema):
+    """Test that routes with no tags are handled correctly with empty lists."""
+    # Modify a route to remove tags
+    if "tags" in bookstore_schema["paths"]["/books"]["get"]:
+        del bookstore_schema["paths"]["/books"]["get"]["tags"]
+
+    # Parse the modified schema
+    routes = parse_openapi_to_http_routes(bookstore_schema)
+
+    # Find the GET /books route
+    get_books = next(
+        (r for r in routes if r.method == "GET" and r.path == "/books"), None
+    )
+    assert get_books is not None
+
+    # Should have an empty list, not None
+    assert get_books.tags == [], "Routes without tags should have empty tag lists"
+
+
+def test_multiple_tags_preserved(bookstore_schema):
+    """Test that multiple tags are preserved during parsing."""
+    # Add multiple tags to a route
+    bookstore_schema["paths"]["/books"]["get"]["tags"] = ["books", "catalog", "api"]
+
+    # Parse the modified schema
+    routes = parse_openapi_to_http_routes(bookstore_schema)
+
+    # Find the GET /books route
+    get_books = next(
+        (r for r in routes if r.method == "GET" and r.path == "/books"), None
+    )
+    assert get_books is not None
+
+    # Should have all tags
+    assert "books" in get_books.tags
+    assert "catalog" in get_books.tags
+    assert "api" in get_books.tags
+    assert len(get_books.tags) == 3
+
+
 # --- Tests for BookStore schema --- #
 
 

tests/utilities/openapi/test_openapi_fastapi.py

@@ -432,3 +432,91 @@ def test_token_dependency_handling(route_map):
         token_headers = [p for p in header_params if p.name == "x-token"]
         assert len(token_headers) == 1, f"Expected x-token header in {op_id}"
         assert token_headers[0].required is True
+
+
+# --- Additional Tag-related Tests --- #
+
+
+def test_all_routes_have_tags(parsed_routes):
+    """Test that all routes have a non-empty tags list."""
+    for route in parsed_routes:
+        assert hasattr(route, "tags"), f"Route {route.path} should have tags attribute"
+        assert route.tags is not None, f"Route {route.path} tags should not be None"
+        # FastAPI adds tags to all routes in our test fixture
+        assert len(route.tags) > 0, f"Route {route.path} should have at least one tag"
+
+
+def test_tag_consistency_across_related_endpoints(route_map):
+    """Test that related endpoints have consistent tags."""
+    # All item endpoints should have the "items" tag
+    item_endpoints = [
+        "list_items",
+        "create_item",
+        "get_item",
+        "update_item",
+        "delete_item",
+    ]
+    for endpoint in item_endpoints:
+        assert "items" in route_map[endpoint].tags, (
+            f"Endpoint {endpoint} should have 'items' tag"
+        )
+
+    # Tag-related endpoints should have both "items" and "tags" tags
+    tag_endpoints = ["update_item_tags", "get_item_tag"]
+    for endpoint in tag_endpoints:
+        assert "items" in route_map[endpoint].tags, (
+            f"Endpoint {endpoint} should have 'items' tag"
+        )
+        assert "tags" in route_map[endpoint].tags, (
+            f"Endpoint {endpoint} should have 'tags' tag"
+        )
+
+
+def test_tag_order_preservation(fastapi_server):
+    """Test that tag order is preserved in the parsed routes."""
+
+    # Add a new endpoint with specifically ordered tags
+    @fastapi_server.get(
+        "/test-tag-order",
+        tags=["first", "second", "third"],
+        operation_id="test_tag_order",
+    )
+    async def test_tag_order():
+        return {"result": "testing tag order"}
+
+    # Get the updated schema and parse routes
+    routes = parse_openapi_to_http_routes(fastapi_server.openapi())
+
+    # Find our test route
+    test_route = next((r for r in routes if r.path == "/test-tag-order"), None)
+    assert test_route is not None
+
+    # Check tag order is preserved
+    assert test_route.tags == ["first", "second", "third"], (
+        "Tag order should be preserved"
+    )
+
+
+def test_duplicate_tags_handling(fastapi_server):
+    """Test handling of duplicate tags in the OpenAPI schema."""
+
+    # Add an endpoint with duplicate tags
+    @fastapi_server.get(
+        "/test-duplicate-tags",
+        tags=["duplicate", "items", "duplicate"],
+        operation_id="test_duplicate_tags",
+    )
+    async def test_duplicate_tags():
+        return {"result": "testing duplicate tags"}
+
+    # Get the updated schema and parse routes
+    routes = parse_openapi_to_http_routes(fastapi_server.openapi())
+
+    # Find our test route
+    test_route = next((r for r in routes if r.path == "/test-duplicate-tags"), None)
+    assert test_route is not None
+
+    # Check that duplicate tags are preserved (FastAPI might deduplicate)
+    # We'll test both possibilities to be safe
+    assert "duplicate" in test_route.tags, "Tag 'duplicate' should be present"
+    assert "items" in test_route.tags, "Tag 'items' should be present"