import base64 import json from pathlib import Path from typing import TYPE_CHECKING import pytest from mcp.shared.exceptions import McpError from mcp.types import ( BlobResourceContents, ImageContent, TextContent, TextResourceContents, ) from pydantic import AnyUrl, Field 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 if TYPE_CHECKING: from fastmcp import Context class TestCreateServer: async def test_create_server(self): mcp = FastMCP(instructions="Server instructions") assert mcp.name == "FastMCP" assert mcp.instructions == "Server instructions" async def test_non_ascii_description(self): """Test that FastMCP handles non-ASCII characters in descriptions correctly""" mcp = FastMCP() @mcp.tool( description=( "🌟 This tool uses emojis and UTF-8 characters: á é í ó ú ñ 漢字 🎉" ) ) def hello_world(name: str = "世界") -> str: return f"¡Hola, {name}! 👋" async with Client(mcp) as client: tools = await client.list_tools() 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) == 1 content = result[0] assert isinstance(content, TextContent) assert "¡Hola, 世界! 👋" == content.text async def test_add_tool_decorator(self): mcp = FastMCP() @mcp.tool() def add(x: int, y: int) -> int: return x + y assert len(mcp._tool_manager.list_tools()) == 1 async def test_add_tool_decorator_incorrect_usage(self): mcp = FastMCP() with pytest.raises(TypeError, match="The @tool decorator was used incorrectly"): @mcp.tool # Missing parentheses #type: ignore def add(x: int, y: int) -> int: return x + y async def test_add_resource_decorator(self): mcp = FastMCP() @mcp.resource("r://{x}") def get_data(x: str) -> str: return f"Data: {x}" assert len(mcp._resource_manager._templates) == 1 async def test_add_resource_decorator_incorrect_usage(self): mcp = FastMCP() with pytest.raises( TypeError, match="The @resource decorator was used incorrectly" ): @mcp.resource # Missing parentheses #type: ignore def get_data(x: str) -> str: return f"Data: {x}" @pytest.fixture def tool_server(): mcp = FastMCP() @mcp.tool() def add(x: int, y: int) -> int: return x + y @mcp.tool() def list_tool() -> list[str | int]: return ["x", 2] @mcp.tool() def error_tool() -> None: raise ValueError("Test error") @mcp.tool() def image_tool(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"), ] return mcp class TestServerTools: 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") 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") 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") @mcp.tool() 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}" tools = await mcp.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" class TestServerResources: 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 TestServerResourceTemplates: async def test_resource_with_params(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="Mismatch between URI parameters"): @mcp.resource("resource://data") def get_data_fn(param: str) -> str: return f"Data: {param}" async def test_resource_with_uri_params(self): """Test that a resource with URI parameters is automatically a template""" mcp = FastMCP() with pytest.raises(ValueError, match="Mismatch between URI parameters"): @mcp.resource("resource://{param}") 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() @mcp.resource("resource://{param}") 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() @mcp.resource("resource://{name}/data") 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="Mismatch between URI parameters"): @mcp.resource("resource://{name}/data") 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() @mcp.resource("resource://{org}/{repo}/data") 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="Mismatch between URI parameters"): @mcp.resource("resource://{org}/{repo}/data") 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() @mcp.resource("resource://static") 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_to_resource_conversion(self): """Test that templates are properly converted to resources when accessed""" mcp = FastMCP() @mcp.resource("resource://{name}/data") def get_data(name: str) -> str: return f"Data for {name}" # Should be registered as a template assert len(mcp._resource_manager._templates) == 1 assert len(await mcp.list_resources()) == 0 # When accessed, should create a concrete resource resource = await mcp._resource_manager.get_resource("resource://test/data") assert isinstance(resource, FunctionResource) result = await resource.read() assert result == "Data for test" 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}" tool = mcp._tool_manager.add_tool_from_fn(tool_with_context) assert tool.context_kwarg == "ctx" 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() @mcp.resource("test://data") def test_resource() -> str: return "resource data" @mcp.tool() 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 class TestServerPrompts: """Test prompt functionality in FastMCP server.""" async def test_prompt_decorator(self): """Test that the prompt decorator registers prompts correctly.""" mcp = FastMCP() @mcp.prompt() def fn() -> str: return "Hello, world!" prompts = mcp._prompt_manager.list_prompts() assert len(prompts) == 1 assert prompts[0].name == "fn" # Don't compare functions directly since validate_call wraps them content = await prompts[0].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() @mcp.prompt(name="custom_name") def fn() -> str: return "Hello, world!" prompts = mcp._prompt_manager.list_prompts() assert len(prompts) == 1 assert prompts[0].name == "custom_name" content = await prompts[0].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() @mcp.prompt(description="A custom description") def fn() -> str: return "Hello, world!" prompts = mcp._prompt_manager.list_prompts() assert len(prompts) == 1 assert prompts[0].description == "A custom description" content = await prompts[0].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"): @mcp.prompt # type: ignore def fn() -> str: return "Hello, world!" async def test_list_prompts(self): """Test listing prompts through MCP protocol.""" mcp = FastMCP() @mcp.prompt() def fn(name: str, optional: str = "default") -> str: return f"Hello, {name}!" async with Client(mcp) as client: result = await client.list_prompts() 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 assert prompt.arguments[0].name == "name" assert prompt.arguments[0].required is True assert prompt.arguments[1].name == "optional" assert prompt.arguments[1].required is False async def test_get_prompt(self): """Test getting a prompt through MCP protocol.""" mcp = FastMCP() @mcp.prompt() 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.messages) == 1 message = result.messages[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() @mcp.prompt() 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.messages[0].role == "user" content = result.messages[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() async with Client(mcp) as client: with pytest.raises(McpError, match="Unknown prompt"): await client.get_prompt("unknown") async def test_get_prompt_missing_args(self): """Test error when required arguments are missing.""" mcp = FastMCP() @mcp.prompt() def prompt_fn(name: str) -> str: return f"Hello, {name}!" async with Client(mcp) as client: with pytest.raises(McpError, match="Missing required arguments"): await client.get_prompt("prompt_fn") async def test_tool_decorator_with_tags(self): """Test that the tool decorator properly sets tags.""" mcp = FastMCP() @mcp.tool(tags={"example", "test-tag"}) def sample_tool(x: int) -> int: return x * 2 # Verify the tags were set correctly tools = mcp._tool_manager.list_tools() assert len(tools) == 1 assert tools[0].tags == {"example", "test-tag"} async def test_resource_decorator_with_tags(self): """Test that the resource decorator properly sets tags.""" mcp = FastMCP() @mcp.resource("resource://sample", tags={"example", "test-tag"}) def sample_resource() -> str: return "Sample resource" # Verify the tags were set correctly resources = mcp._resource_manager.list_resources() 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() @mcp.resource("resource://{param}", tags={"template", "test-tag"}) def template_resource(param: str) -> str: return f"Template resource: {param}" templates = mcp._resource_manager.list_templates() assert len(templates) == 1 assert templates[0].tags == {"template", "test-tag"} async def test_prompt_decorator_with_tags(self): """Test that the prompt decorator properly sets tags.""" mcp = FastMCP() @mcp.prompt(tags={"example", "test-tag"}) def sample_prompt() -> str: return "Sample prompt" # Verify the tags were set correctly prompts = mcp._prompt_manager.list_prompts() assert len(prompts) == 1 assert prompts[0].tags == {"example", "test-tag"}