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| import base64 | |
| import datetime | |
| import json | |
| import uuid | |
| from enum import Enum | |
| from pathlib import Path | |
| from typing import Annotated, Literal | |
| import pytest | |
| from mcp.types import ( | |
| BlobResourceContents, | |
| ImageContent, | |
| TextContent, | |
| TextResourceContents, | |
| ) | |
| from pydantic import AnyUrl, Field | |
| from fastmcp import Client, Context, FastMCP | |
| from fastmcp.exceptions import ClientError | |
| from fastmcp.prompts.prompt import EmbeddedResource, Message, UserMessage | |
| from fastmcp.resources import FileResource, FunctionResource | |
| from fastmcp.utilities.types import Image | |
| def tool_server(): | |
| mcp = FastMCP() | |
| def add(x: int, y: int) -> int: | |
| return x + y | |
| def list_tool() -> list[str | int]: | |
| return ["x", 2] | |
| def error_tool() -> None: | |
| raise ValueError("Test error") | |
| def image_tool(path: str) -> Image: | |
| return Image(path) | |
| def mixed_content_tool() -> list[TextContent | ImageContent]: | |
| return [ | |
| TextContent(type="text", text="Hello"), | |
| ImageContent(type="image", data="abc", mimeType="image/png"), | |
| ] | |
| def mixed_list_fn(image_path: str) -> list: | |
| return [ | |
| "text message", | |
| Image(image_path), | |
| {"key": "value"}, | |
| TextContent(type="text", text="direct content"), | |
| ] | |
| return mcp | |
| class TestTools: | |
| async def test_add_tool_exists(self, tool_server: FastMCP): | |
| async with Client(tool_server) as client: | |
| tools = await client.list_tools() | |
| assert "add" in [t.name for t in tools] | |
| async def test_list_tools(self, tool_server: FastMCP): | |
| async with Client(tool_server) as client: | |
| assert len(await client.list_tools()) == 6 | |
| async def test_call_tool(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_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): | |
| 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(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): | |
| async with Client(tool_server) as client: | |
| result = await client.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") | |
| async with Client(tool_server) as client: | |
| result = await client.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): | |
| async with Client(tool_server) as client: | |
| result = await client.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") | |
| async with Client(tool_server) as client: | |
| result = await client.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" | |
| class TestToolParameters: | |
| async def test_parameter_descriptions_with_field_annotations(self): | |
| mcp = FastMCP("Test Server") | |
| def greet( | |
| name: Annotated[str, Field(description="The name to greet")], | |
| title: Annotated[str, Field(description="Optional title", default="")], | |
| ) -> str: | |
| """A greeting tool""" | |
| return f"Hello {title} {name}" | |
| async with Client(mcp) as client: | |
| tools = await client.list_tools() | |
| assert len(tools) == 1 | |
| tool = tools[0] | |
| # Check that parameter descriptions are present in the schema | |
| properties = tool.inputSchema["properties"] | |
| assert "name" in properties | |
| assert properties["name"]["description"] == "The name to greet" | |
| assert "title" in properties | |
| assert properties["title"]["description"] == "Optional title" | |
| assert properties["title"]["default"] == "" | |
| assert tool.inputSchema["required"] == ["name"] | |
| async def test_parameter_descriptions_with_field_defaults(self): | |
| mcp = FastMCP("Test Server") | |
| def greet( | |
| name: str = Field(description="The name to greet"), | |
| title: str = Field(description="Optional title", default=""), | |
| ) -> str: | |
| """A greeting tool""" | |
| return f"Hello {title} {name}" | |
| async with Client(mcp) as client: | |
| tools = await client.list_tools() | |
| assert len(tools) == 1 | |
| tool = tools[0] | |
| # Check that parameter descriptions are present in the schema | |
| properties = tool.inputSchema["properties"] | |
| assert "name" in properties | |
| assert properties["name"]["description"] == "The name to greet" | |
| assert "title" in properties | |
| assert properties["title"]["description"] == "Optional title" | |
| assert properties["title"]["default"] == "" | |
| assert tool.inputSchema["required"] == ["name"] | |
| async def test_tool_with_bytes_input(self): | |
| mcp = FastMCP() | |
| def process_image(image: bytes) -> Image: | |
| return Image(data=image) | |
| async with Client(mcp) as client: | |
| result = await client.call_tool( | |
| "process_image", {"image": b"fake png data"} | |
| ) | |
| assert isinstance(result[0], ImageContent) | |
| assert result[0].mimeType == "image/png" | |
| assert result[0].data == base64.b64encode(b"fake png data").decode() | |
| async def test_tool_with_invalid_input(self): | |
| mcp = FastMCP() | |
| def my_tool(x: int) -> int: | |
| return x + 1 | |
| async with Client(mcp) as client: | |
| with pytest.raises( | |
| ClientError, | |
| match="Input should be a valid integer, unable to parse string as an integer", | |
| ): | |
| await client.call_tool("my_tool", {"x": "not an int"}) | |
| async def test_tool_int_coercion(self): | |
| """Test string-to-int type coercion.""" | |
| mcp = FastMCP() | |
| def add_one(x: int) -> int: | |
| return x + 1 | |
| async with Client(mcp) as client: | |
| # String with integer value should be coerced to int | |
| result = await client.call_tool("add_one", {"x": "42"}) | |
| assert isinstance(result[0], TextContent) | |
| assert result[0].text == "43" | |
| async def test_tool_bool_coercion(self): | |
| """Test string-to-bool type coercion.""" | |
| mcp = FastMCP() | |
| def toggle(flag: bool) -> bool: | |
| return not flag | |
| async with Client(mcp) as client: | |
| # String with boolean value should be coerced to bool | |
| result = await client.call_tool("toggle", {"flag": "true"}) | |
| assert isinstance(result[0], TextContent) | |
| assert result[0].text == "false" | |
| result = await client.call_tool("toggle", {"flag": "false"}) | |
| assert isinstance(result[0], TextContent) | |
| assert result[0].text == "true" | |
| async def test_tool_list_coercion(self): | |
| """Test JSON string to collection type coercion.""" | |
| mcp = FastMCP() | |
| def process_list(items: list[int]) -> int: | |
| return sum(items) | |
| async with Client(mcp) as client: | |
| # JSON array string should be coerced to list | |
| result = await client.call_tool( | |
| "process_list", {"items": "[1, 2, 3, 4, 5]"} | |
| ) | |
| assert isinstance(result[0], TextContent) | |
| assert result[0].text == "15" | |
| async def test_tool_list_coercion_error(self): | |
| """Test that a list coercion error is raised if the input is not a valid list.""" | |
| mcp = FastMCP() | |
| def process_list(items: list[int]) -> int: | |
| return sum(items) | |
| async with Client(mcp) as client: | |
| with pytest.raises( | |
| ClientError, | |
| match="Input should be a valid list", | |
| ): | |
| await client.call_tool("process_list", {"items": "['a', 'b', 3]"}) | |
| async def test_tool_dict_coercion(self): | |
| """Test JSON string to dict type coercion.""" | |
| mcp = FastMCP() | |
| def process_dict(data: dict[str, int]) -> int: | |
| return sum(data.values()) | |
| async with Client(mcp) as client: | |
| # JSON object string should be coerced to dict | |
| result = await client.call_tool( | |
| "process_dict", {"data": '{"a": 1, "b": "2", "c": 3}'} | |
| ) | |
| assert isinstance(result[0], TextContent) | |
| assert result[0].text == "6" | |
| async def test_tool_set_coercion(self): | |
| """Test JSON string to set type coercion.""" | |
| mcp = FastMCP() | |
| def process_set(items: set[int]) -> int: | |
| assert isinstance(items, set) | |
| return sum(items) | |
| async with Client(mcp) as client: | |
| result = await client.call_tool("process_set", {"items": "[1, 2, 3, 4, 5]"}) | |
| assert isinstance(result[0], TextContent) | |
| assert result[0].text == "15" | |
| async def test_tool_tuple_coercion(self): | |
| """Test JSON string to tuple type coercion.""" | |
| mcp = FastMCP() | |
| def process_tuple(items: tuple[int, str]) -> int: | |
| assert isinstance(items, tuple) | |
| return items[0] + len(items[1]) | |
| async with Client(mcp) as client: | |
| result = await client.call_tool("process_tuple", {"items": '["1", "two"]'}) | |
| assert isinstance(result[0], TextContent) | |
| assert result[0].text == "4" | |
| async def test_annotated_field_validation(self): | |
| mcp = FastMCP() | |
| def analyze(x: Annotated[int, Field(ge=1)]) -> None: | |
| pass | |
| async with Client(mcp) as client: | |
| with pytest.raises( | |
| ClientError, | |
| match="Input should be greater than or equal to 1", | |
| ): | |
| await client.call_tool("analyze", {"x": 0}) | |
| async def test_default_field_validation(self): | |
| mcp = FastMCP() | |
| def analyze(x: int = Field(ge=1)) -> None: | |
| pass | |
| async with Client(mcp) as client: | |
| with pytest.raises( | |
| ClientError, | |
| match="Input should be greater than or equal to 1", | |
| ): | |
| await client.call_tool("analyze", {"x": 0}) | |
| async def test_default_field_is_still_required_if_no_default_specified(self): | |
| mcp = FastMCP() | |
| def analyze(x: int = Field()) -> None: | |
| pass | |
| async with Client(mcp) as client: | |
| with pytest.raises(ClientError, match="Field required"): | |
| await client.call_tool("analyze", {}) | |
| async def test_literal_type_validation_error(self): | |
| mcp = FastMCP() | |
| def analyze(x: Literal["a", "b"]) -> None: | |
| pass | |
| async with Client(mcp) as client: | |
| with pytest.raises(ClientError, match="Input should be 'a' or 'b'"): | |
| await client.call_tool("analyze", {"x": "c"}) | |
| async def test_literal_type_validation_success(self): | |
| mcp = FastMCP() | |
| def analyze(x: Literal["a", "b"]) -> str: | |
| return x | |
| async with Client(mcp) as client: | |
| result = await client.call_tool("analyze", {"x": "a"}) | |
| assert isinstance(result[0], TextContent) | |
| assert result[0].text == "a" | |
| async def test_enum_type_validation_error(self): | |
| mcp = FastMCP() | |
| class MyEnum(Enum): | |
| RED = "red" | |
| GREEN = "green" | |
| BLUE = "blue" | |
| def analyze(x: MyEnum) -> str: | |
| return x.value | |
| async with Client(mcp) as client: | |
| with pytest.raises( | |
| ClientError, match="Input should be 'red', 'green' or 'blue'" | |
| ): | |
| await client.call_tool("analyze", {"x": "some-color"}) | |
| async def test_enum_type_validation_success(self): | |
| mcp = FastMCP() | |
| class MyEnum(Enum): | |
| RED = "red" | |
| GREEN = "green" | |
| BLUE = "blue" | |
| def analyze(x: MyEnum) -> str: | |
| return x.value | |
| async with Client(mcp) as client: | |
| result = await client.call_tool("analyze", {"x": "red"}) | |
| assert isinstance(result[0], TextContent) | |
| assert result[0].text == "red" | |
| async def test_union_type_validation(self): | |
| mcp = FastMCP() | |
| def analyze(x: int | float) -> str: | |
| return str(x) | |
| async with Client(mcp) as client: | |
| result = await client.call_tool("analyze", {"x": 1}) | |
| assert isinstance(result[0], TextContent) | |
| assert result[0].text == "1" | |
| result = await client.call_tool("analyze", {"x": 1.0}) | |
| assert isinstance(result[0], TextContent) | |
| assert result[0].text == "1.0" | |
| with pytest.raises(ClientError, match="2 validation errors for analyze"): | |
| await client.call_tool("analyze", {"x": "not a number"}) | |
| async def test_path_type(self): | |
| mcp = FastMCP() | |
| def send_path(path: Path) -> str: | |
| assert isinstance(path, Path) | |
| return str(path) | |
| async with Client(mcp) as client: | |
| result = await client.call_tool("send_path", {"path": "/tmp/test.txt"}) | |
| assert isinstance(result[0], TextContent) | |
| assert result[0].text == "/tmp/test.txt" | |
| async def test_path_type_error(self): | |
| mcp = FastMCP() | |
| def send_path(path: Path) -> str: | |
| return str(path) | |
| async with Client(mcp) as client: | |
| with pytest.raises(ClientError, match="Input is not a valid path"): | |
| await client.call_tool("send_path", {"path": 1}) | |
| async def test_uuid_type(self): | |
| mcp = FastMCP() | |
| def send_uuid(x: uuid.UUID) -> str: | |
| assert isinstance(x, uuid.UUID) | |
| return str(x) | |
| test_uuid = uuid.uuid4() | |
| async with Client(mcp) as client: | |
| result = await client.call_tool("send_uuid", {"x": test_uuid}) | |
| assert isinstance(result[0], TextContent) | |
| assert result[0].text == str(test_uuid) | |
| async def test_uuid_type_error(self): | |
| mcp = FastMCP() | |
| def send_uuid(x: uuid.UUID) -> str: | |
| return str(x) | |
| async with Client(mcp) as client: | |
| with pytest.raises(ClientError, match="Input should be a valid UUID"): | |
| await client.call_tool("send_uuid", {"x": "not a uuid"}) | |
| async def test_datetime_type(self): | |
| mcp = FastMCP() | |
| def send_datetime(x: datetime.datetime) -> str: | |
| return x.isoformat() | |
| dt = datetime.datetime(2025, 4, 25, 1, 2, 3) | |
| async with Client(mcp) as client: | |
| result = await client.call_tool("send_datetime", {"x": dt}) | |
| assert isinstance(result[0], TextContent) | |
| assert result[0].text == dt.isoformat() | |
| async def test_datetime_type_parse_string(self): | |
| mcp = FastMCP() | |
| def send_datetime(x: datetime.datetime) -> str: | |
| return x.isoformat() | |
| async with Client(mcp) as client: | |
| result = await client.call_tool( | |
| "send_datetime", {"x": "2021-01-01T00:00:00"} | |
| ) | |
| assert isinstance(result[0], TextContent) | |
| assert result[0].text == "2021-01-01T00:00:00" | |
| async def test_datetime_type_error(self): | |
| mcp = FastMCP() | |
| def send_datetime(x: datetime.datetime) -> str: | |
| return x.isoformat() | |
| async with Client(mcp) as client: | |
| with pytest.raises(ClientError, match="Input should be a valid datetime"): | |
| await client.call_tool("send_datetime", {"x": "not a datetime"}) | |
| async def test_date_type(self): | |
| mcp = FastMCP() | |
| def send_date(x: datetime.date) -> str: | |
| return x.isoformat() | |
| async with Client(mcp) as client: | |
| result = await client.call_tool("send_date", {"x": datetime.date.today()}) | |
| assert isinstance(result[0], TextContent) | |
| assert result[0].text == datetime.date.today().isoformat() | |
| async def test_date_type_parse_string(self): | |
| mcp = FastMCP() | |
| def send_date(x: datetime.date) -> str: | |
| return x.isoformat() | |
| async with Client(mcp) as client: | |
| result = await client.call_tool("send_date", {"x": "2021-01-01"}) | |
| assert isinstance(result[0], TextContent) | |
| assert result[0].text == "2021-01-01" | |
| async def test_timedelta_type(self): | |
| mcp = FastMCP() | |
| def send_timedelta(x: datetime.timedelta) -> str: | |
| return str(x) | |
| async with Client(mcp) as client: | |
| result = await client.call_tool( | |
| "send_timedelta", {"x": datetime.timedelta(days=1)} | |
| ) | |
| assert isinstance(result[0], TextContent) | |
| assert result[0].text == "1 day, 0:00:00" | |
| async def test_timedelta_type_parse_int(self): | |
| mcp = FastMCP() | |
| def send_timedelta(x: datetime.timedelta) -> str: | |
| return str(x) | |
| async with Client(mcp) as client: | |
| result = await client.call_tool("send_timedelta", {"x": 1000}) | |
| assert isinstance(result[0], TextContent) | |
| assert result[0].text == "0:16:40" | |
| class TestResources: | |
| async def test_text_resource(self): | |
| mcp = FastMCP() | |
| def get_text(): | |
| return "Hello, world!" | |
| resource = FunctionResource( | |
| uri=AnyUrl("resource://test"), name="test", fn=get_text | |
| ) | |
| mcp.add_resource(resource) | |
| async with Client(mcp) as client: | |
| result = await client.read_resource(AnyUrl("resource://test")) | |
| assert isinstance(result[0], TextResourceContents) | |
| assert result[0].text == "Hello, world!" | |
| async def test_binary_resource(self): | |
| mcp = FastMCP() | |
| def get_binary(): | |
| return b"Binary data" | |
| resource = FunctionResource( | |
| uri=AnyUrl("resource://binary"), | |
| name="binary", | |
| fn=get_binary, | |
| mime_type="application/octet-stream", | |
| ) | |
| mcp.add_resource(resource) | |
| async with Client(mcp) as client: | |
| result = await client.read_resource(AnyUrl("resource://binary")) | |
| 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() | |
| # Create a text file | |
| text_file = tmp_path / "test.txt" | |
| text_file.write_text("Hello from file!") | |
| resource = FileResource( | |
| uri=AnyUrl("file://test.txt"), name="test.txt", path=text_file | |
| ) | |
| mcp.add_resource(resource) | |
| async with Client(mcp) as client: | |
| result = await client.read_resource(AnyUrl("file://test.txt")) | |
| assert isinstance(result[0], TextResourceContents) | |
| assert result[0].text == "Hello from file!" | |
| async def test_file_resource_binary(self, tmp_path: Path): | |
| mcp = FastMCP() | |
| # Create a binary file | |
| binary_file = tmp_path / "test.bin" | |
| binary_file.write_bytes(b"Binary file data") | |
| resource = FileResource( | |
| uri=AnyUrl("file://test.bin"), | |
| name="test.bin", | |
| path=binary_file, | |
| mime_type="application/octet-stream", | |
| ) | |
| mcp.add_resource(resource) | |
| async with Client(mcp) as client: | |
| result = await client.read_resource(AnyUrl("file://test.bin")) | |
| assert isinstance(result[0], BlobResourceContents) | |
| assert result[0].blob == base64.b64encode(b"Binary file data").decode() | |
| class TestResourceTemplates: | |
| async def test_resource_with_params_not_in_uri(self): | |
| """Test that a resource with function parameters raises an error if the URI | |
| parameters don't match""" | |
| mcp = FastMCP() | |
| with pytest.raises( | |
| ValueError, | |
| match="URI template must contain at least one parameter", | |
| ): | |
| def get_data_fn(param: str) -> str: | |
| return f"Data: {param}" | |
| async def test_resource_with_uri_params_without_args(self): | |
| """Test that a resource with URI parameters is automatically a template""" | |
| mcp = FastMCP() | |
| with pytest.raises( | |
| ValueError, | |
| match="URI parameters .* must be a subset of the function arguments", | |
| ): | |
| def get_data() -> str: | |
| return "Data" | |
| async def test_resource_with_untyped_params(self): | |
| """Test that a resource with untyped parameters raises an error""" | |
| mcp = FastMCP() | |
| def get_data(param) -> str: | |
| return "Data" | |
| async def test_resource_matching_params(self): | |
| """Test that a resource with matching URI and function parameters works""" | |
| mcp = FastMCP() | |
| def get_data(name: str) -> str: | |
| return f"Data for {name}" | |
| async with Client(mcp) as client: | |
| result = await client.read_resource(AnyUrl("resource://test/data")) | |
| 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""" | |
| mcp = FastMCP() | |
| with pytest.raises( | |
| ValueError, | |
| match="URI parameters .* must be a subset of the required function arguments", | |
| ): | |
| def get_data(user: str) -> str: | |
| return f"Data for {user}" | |
| async def test_resource_multiple_params(self): | |
| """Test that multiple parameters work correctly""" | |
| mcp = FastMCP() | |
| def get_data(org: str, repo: str) -> str: | |
| return f"Data for {org}/{repo}" | |
| async with Client(mcp) as client: | |
| result = await client.read_resource( | |
| AnyUrl("resource://cursor/fastmcp/data") | |
| ) | |
| 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""" | |
| mcp = FastMCP() | |
| with pytest.raises( | |
| ValueError, | |
| match="URI parameters .* must be a subset of the required function arguments", | |
| ): | |
| def get_data_mismatched(org: str, repo_2: str) -> str: | |
| return f"Data for {org}" | |
| """Test that a resource with no parameters works as a regular resource""" | |
| mcp = FastMCP() | |
| def get_static_data() -> str: | |
| return "Static data" | |
| async with Client(mcp) as client: | |
| result = await client.read_resource(AnyUrl("resource://static")) | |
| assert isinstance(result[0], TextResourceContents) | |
| assert result[0].text == "Static data" | |
| async def test_template_with_default_params(self): | |
| """Test that a template can have default parameters.""" | |
| mcp = FastMCP() | |
| def add(x: int, y: int = 10) -> int: | |
| return x + y | |
| # Verify it's registered as a template | |
| templates_dict = await mcp.get_resource_templates() | |
| templates = list(templates_dict.values()) | |
| assert len(templates) == 1 | |
| assert templates[0].uri_template == "math://add/{x}" | |
| # Call the template and verify it uses the default value | |
| async with Client(mcp) as client: | |
| result = await client.read_resource(AnyUrl("math://add/5")) | |
| assert isinstance(result[0], TextResourceContents) | |
| assert result[0].text == "15" # 5 + default 10 | |
| # Can also call with explicit params | |
| result2 = await client.read_resource(AnyUrl("math://add/7")) | |
| assert isinstance(result2[0], TextResourceContents) | |
| assert result2[0].text == "17" # 7 + default 10 | |
| async def test_template_to_resource_conversion(self): | |
| """Test that a template can be converted to a resource.""" | |
| mcp = FastMCP() | |
| def get_data(name: str) -> str: | |
| return f"Data for {name}" | |
| # Verify it's registered as a template | |
| templates_dict = await mcp.get_resource_templates() | |
| templates = list(templates_dict.values()) | |
| assert len(templates) == 1 | |
| assert templates[0].uri_template == "resource://{name}/data" | |
| # When accessed, should create a concrete resource | |
| async with Client(mcp) as client: | |
| result = await client.read_resource(AnyUrl("resource://test/data")) | |
| assert isinstance(result[0], TextResourceContents) | |
| assert result[0].text == "Data for test" | |
| async def test_stacked_resource_template_decorators(self): | |
| """Test that resource template decorators can be stacked.""" | |
| mcp = FastMCP() | |
| def lookup_user(name: str | None = None, email: str | None = None) -> dict: | |
| if name: | |
| return { | |
| "id": "123", | |
| "name": name, | |
| "email": "dummy@example.com", | |
| "lookup": "name", | |
| } | |
| elif email: | |
| return { | |
| "id": "123", | |
| "name": "Test User", | |
| "email": email, | |
| "lookup": "email", | |
| } | |
| else: | |
| raise ValueError("Either name or email must be provided") | |
| # Verify both templates are registered | |
| templates_dict = await mcp.get_resource_templates() | |
| templates = list(templates_dict.values()) | |
| assert len(templates) == 2 | |
| template_uris = {t.uri_template for t in templates} | |
| assert "users://email/{email}" in template_uris | |
| assert "users://name/{name}" in template_uris | |
| # Test lookup by email | |
| async with Client(mcp) as client: | |
| email_result = await client.read_resource( | |
| AnyUrl("users://email/user@example.com") | |
| ) | |
| assert isinstance(email_result[0], TextResourceContents) | |
| email_data = json.loads(email_result[0].text) | |
| assert email_data["lookup"] == "email" | |
| assert email_data["email"] == "user@example.com" | |
| # Test lookup by name | |
| name_result = await client.read_resource(AnyUrl("users://name/John")) | |
| assert isinstance(name_result[0], TextResourceContents) | |
| name_data = json.loads(name_result[0].text) | |
| assert name_data["lookup"] == "name" | |
| assert name_data["name"] == "John" | |
| assert name_data["email"] == "dummy@example.com" | |
| async def test_template_decorator_with_tags(self): | |
| mcp = FastMCP() | |
| def template_resource(param: str) -> str: | |
| return f"Template resource: {param}" | |
| templates_dict = await mcp.get_resource_templates() | |
| template = templates_dict["resource://{param}"] | |
| assert template.tags == {"template", "test-tag"} | |
| async def test_template_decorator_wildcard_param(self): | |
| mcp = FastMCP() | |
| def template_resource(param: str) -> str: | |
| return f"Template resource: {param}" | |
| async with Client(mcp) as client: | |
| result = await client.read_resource(AnyUrl("resource://test/data")) | |
| assert isinstance(result[0], TextResourceContents) | |
| assert result[0].text == "Template resource: test/data" | |
| async def test_templates_match_in_order_of_definition(self): | |
| """ | |
| If a wildcard template is defined first, it will take priority over another | |
| matching template. | |
| """ | |
| mcp = FastMCP() | |
| def template_resource(param: str) -> str: | |
| return f"Template resource 1: {param}" | |
| def template_resource_with_params(x: str, y: str) -> str: | |
| return f"Template resource 2: {x}/{y}" | |
| async with Client(mcp) as client: | |
| result = await client.read_resource(AnyUrl("resource://a/b/c")) | |
| assert isinstance(result[0], TextResourceContents) | |
| assert result[0].text == "Template resource 1: a/b/c" | |
| result = await client.read_resource(AnyUrl("resource://a/b")) | |
| assert isinstance(result[0], TextResourceContents) | |
| assert result[0].text == "Template resource 1: a/b" | |
| async def test_templates_shadow_each_other_reorder(self): | |
| """ | |
| If a wildcard template is defined second, it will *not* take priority over | |
| another matching template. | |
| """ | |
| mcp = FastMCP() | |
| def template_resource_with_params(x: str, y: str) -> str: | |
| return f"Template resource 1: {x}/{y}" | |
| def template_resource(param: str) -> str: | |
| return f"Template resource 2: {param}" | |
| async with Client(mcp) as client: | |
| result = await client.read_resource(AnyUrl("resource://a/b/c")) | |
| assert isinstance(result[0], TextResourceContents) | |
| assert result[0].text == "Template resource 2: a/b/c" | |
| result = await client.read_resource(AnyUrl("resource://a/b")) | |
| assert isinstance(result[0], TextResourceContents) | |
| assert result[0].text == "Template resource 1: a/b" | |
| class TestContextInjection: | |
| """Test context injection in tools.""" | |
| async def test_context_detection(self): | |
| """Test that context parameters are properly detected.""" | |
| mcp = FastMCP() | |
| def tool_with_context(x: int, ctx: Context) -> str: | |
| return f"Request {ctx.request_id}: {x}" | |
| mcp.add_tool(tool_with_context) | |
| async with Client(mcp) as client: | |
| tools = await client.list_tools() | |
| assert len(tools) == 1 | |
| assert tools[0].name == "tool_with_context" | |
| async def test_context_injection(self): | |
| """Test that context is properly injected into tool calls.""" | |
| mcp = FastMCP() | |
| def tool_with_context(x: int, ctx: Context) -> str: | |
| assert ctx.request_id is not None | |
| return f"Request {ctx.request_id}: {x}" | |
| mcp.add_tool(tool_with_context) | |
| async with Client(mcp) as client: | |
| result = await client.call_tool("tool_with_context", {"x": 42}) | |
| assert len(result) == 1 | |
| content = result[0] | |
| assert isinstance(content, TextContent) | |
| assert "Request" in content.text | |
| assert "42" in content.text | |
| async def test_async_context(self): | |
| """Test that context works in async functions.""" | |
| mcp = FastMCP() | |
| async def async_tool(x: int, ctx: Context) -> str: | |
| assert ctx.request_id is not None | |
| return f"Async request {ctx.request_id}: {x}" | |
| mcp.add_tool(async_tool) | |
| async with Client(mcp) as client: | |
| result = await client.call_tool("async_tool", {"x": 42}) | |
| assert len(result) == 1 | |
| content = result[0] | |
| assert isinstance(content, TextContent) | |
| assert "Async request" in content.text | |
| assert "42" in content.text | |
| async def test_context_logging(self): | |
| from unittest.mock import patch | |
| import mcp.server.session | |
| """Test that context logging methods work.""" | |
| mcp = FastMCP() | |
| async def logging_tool(msg: str, ctx: Context) -> str: | |
| await ctx.debug("Debug message") | |
| await ctx.info("Info message") | |
| await ctx.warning("Warning message") | |
| await ctx.error("Error message") | |
| return f"Logged messages for {msg}" | |
| mcp.add_tool(logging_tool) | |
| with patch("mcp.server.session.ServerSession.send_log_message") as mock_log: | |
| async with Client(mcp) as client: | |
| result = await client.call_tool("logging_tool", {"msg": "test"}) | |
| assert len(result) == 1 | |
| content = result[0] | |
| assert isinstance(content, TextContent) | |
| assert "Logged messages for test" in content.text | |
| assert mock_log.call_count == 4 | |
| mock_log.assert_any_call( | |
| level="debug", data="Debug message", logger=None | |
| ) | |
| mock_log.assert_any_call(level="info", data="Info message", logger=None) | |
| mock_log.assert_any_call( | |
| level="warning", data="Warning message", logger=None | |
| ) | |
| mock_log.assert_any_call( | |
| level="error", data="Error message", logger=None | |
| ) | |
| async def test_optional_context(self): | |
| """Test that context is optional.""" | |
| mcp = FastMCP() | |
| def no_context(x: int) -> int: | |
| return x * 2 | |
| mcp.add_tool(no_context) | |
| async with Client(mcp) as client: | |
| result = await client.call_tool("no_context", {"x": 21}) | |
| assert len(result) == 1 | |
| content = result[0] | |
| assert isinstance(content, TextContent) | |
| assert content.text == "42" | |
| async def test_context_resource_access(self): | |
| """Test that context can access resources.""" | |
| mcp = FastMCP() | |
| def test_resource() -> str: | |
| return "resource data" | |
| async def tool_with_resource(ctx: Context) -> str: | |
| r_iter = await ctx.read_resource("test://data") | |
| r_list = list(r_iter) | |
| assert len(r_list) == 1 | |
| r = r_list[0] | |
| return f"Read resource: {r.content} with mime type {r.mime_type}" | |
| async with Client(mcp) as client: | |
| result = await client.call_tool("tool_with_resource", {}) | |
| assert len(result) == 1 | |
| content = result[0] | |
| assert isinstance(content, TextContent) | |
| assert "Read resource: resource data" in content.text | |
| async def test_tool_decorator_with_tags(self): | |
| """Test that the tool decorator properly sets tags.""" | |
| mcp = FastMCP() | |
| def sample_tool(x: int) -> int: | |
| return x * 2 | |
| # Verify the tool exists | |
| async with Client(mcp) as client: | |
| tools = await client.list_tools() | |
| assert len(tools) == 1 | |
| # Note: MCPTool from the client API doesn't expose tags | |
| class TestPrompts: | |
| """Test prompt functionality in FastMCP server.""" | |
| async def test_prompt_decorator(self): | |
| """Test that the prompt decorator registers prompts correctly.""" | |
| mcp = FastMCP() | |
| def fn() -> str: | |
| return "Hello, world!" | |
| prompts_dict = await mcp.get_prompts() | |
| assert len(prompts_dict) == 1 | |
| prompt = prompts_dict["fn"] | |
| assert prompt.name == "fn" | |
| # Don't compare functions directly since validate_call wraps them | |
| content = await prompt.render() | |
| assert isinstance(content[0].content, TextContent) | |
| assert content[0].content.text == "Hello, world!" | |
| async def test_prompt_decorator_with_name(self): | |
| """Test prompt decorator with custom name.""" | |
| mcp = FastMCP() | |
| def fn() -> str: | |
| return "Hello, world!" | |
| prompts_dict = await mcp.get_prompts() | |
| assert len(prompts_dict) == 1 | |
| prompt = prompts_dict["custom_name"] | |
| assert prompt.name == "custom_name" | |
| content = await prompt.render() | |
| assert isinstance(content[0].content, TextContent) | |
| assert content[0].content.text == "Hello, world!" | |
| async def test_prompt_decorator_with_description(self): | |
| """Test prompt decorator with custom description.""" | |
| mcp = FastMCP() | |
| def fn() -> str: | |
| return "Hello, world!" | |
| prompts_dict = await mcp.get_prompts() | |
| assert len(prompts_dict) == 1 | |
| prompt = prompts_dict["fn"] | |
| assert prompt.description == "A custom description" | |
| content = await prompt.render() | |
| assert isinstance(content[0].content, TextContent) | |
| assert content[0].content.text == "Hello, world!" | |
| def test_prompt_decorator_error(self): | |
| """Test error when decorator is used incorrectly.""" | |
| mcp = FastMCP() | |
| with pytest.raises(TypeError, match="decorator was used incorrectly"): | |
| # type: ignore | |
| def fn() -> str: | |
| return "Hello, world!" | |
| async def test_list_prompts(self): | |
| """Test listing prompts through MCP protocol.""" | |
| mcp = FastMCP() | |
| def fn(name: str, optional: str = "default") -> str: | |
| return f"Hello, {name}! {optional}" | |
| prompts_dict = await mcp.get_prompts() | |
| assert len(prompts_dict) == 1 | |
| async with Client(mcp) as client: | |
| prompts = await client.list_prompts() | |
| assert len(prompts) == 1 | |
| assert prompts[0].name == "fn" | |
| assert prompts[0].description is None | |
| assert prompts[0].arguments is not None | |
| assert len(prompts[0].arguments) == 2 | |
| assert prompts[0].arguments[0].name == "name" | |
| assert prompts[0].arguments[0].required is True | |
| assert prompts[0].arguments[1].name == "optional" | |
| assert prompts[0].arguments[1].required is False | |
| async def test_get_prompt(self): | |
| """Test getting a prompt through MCP protocol.""" | |
| mcp = FastMCP() | |
| def fn(name: str) -> str: | |
| return f"Hello, {name}!" | |
| async with Client(mcp) as client: | |
| result = await client.get_prompt("fn", {"name": "World"}) | |
| assert len(result) == 1 | |
| message = result[0] | |
| assert message.role == "user" | |
| content = message.content | |
| assert isinstance(content, TextContent) | |
| assert content.text == "Hello, World!" | |
| async def test_get_prompt_with_resource(self): | |
| """Test getting a prompt that returns resource content.""" | |
| mcp = FastMCP() | |
| def fn() -> Message: | |
| return UserMessage( | |
| content=EmbeddedResource( | |
| type="resource", | |
| resource=TextResourceContents( | |
| uri=AnyUrl("file://file.txt"), | |
| text="File contents", | |
| mimeType="text/plain", | |
| ), | |
| ) | |
| ) | |
| async with Client(mcp) as client: | |
| result = await client.get_prompt("fn") | |
| assert result[0].role == "user" | |
| content = result[0].content | |
| assert isinstance(content, EmbeddedResource) | |
| resource = content.resource | |
| assert isinstance(resource, TextResourceContents) | |
| assert resource.text == "File contents" | |
| assert resource.mimeType == "text/plain" | |
| async def test_get_unknown_prompt(self): | |
| """Test error when getting unknown prompt.""" | |
| mcp = FastMCP() | |
| with pytest.raises(ClientError, match="Unknown prompt"): | |
| async with Client(mcp) as client: | |
| await client.get_prompt("unknown") | |
| async def test_get_prompt_missing_args(self): | |
| """Test error when required arguments are missing.""" | |
| mcp = FastMCP() | |
| def prompt_fn(name: str) -> str: | |
| return f"Hello, {name}!" | |
| with pytest.raises(ClientError, match="Missing required arguments"): | |
| async with Client(mcp) as client: | |
| await client.get_prompt("prompt_fn") | |
| async def test_resource_decorator_with_tags(self): | |
| """Test that the resource decorator supports tags.""" | |
| mcp = FastMCP() | |
| def get_data() -> str: | |
| return "Hello, world!" | |
| resources_dict = await mcp.get_resources() | |
| resources = list(resources_dict.values()) | |
| assert len(resources) == 1 | |
| assert resources[0].tags == {"example", "test-tag"} | |
| async def test_template_decorator_with_tags(self): | |
| """Test that the template decorator properly sets tags.""" | |
| mcp = FastMCP() | |
| def template_resource(param: str) -> str: | |
| return f"Template resource: {param}" | |
| templates_dict = await mcp.get_resource_templates() | |
| template = templates_dict["resource://{param}"] | |
| assert template.tags == {"template", "test-tag"} | |
| async def test_prompt_decorator_with_tags(self): | |
| """Test that the prompt decorator properly sets tags.""" | |
| mcp = FastMCP() | |
| def sample_prompt() -> str: | |
| return "Hello, world!" | |
| prompts_dict = await mcp.get_prompts() | |
| assert len(prompts_dict) == 1 | |
| prompt = prompts_dict["sample_prompt"] | |
| assert prompt.tags == {"example", "test-tag"} | |