import base64 import json from pathlib import Path 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 @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 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" 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}" 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" 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", ): @mcp.resource("resource://data") 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", ): @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="URI parameters .* must be a subset of the required function arguments", ): @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="URI parameters .* must be a subset of the required function arguments", ): @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_with_default_params(self): """Test that a template can have default parameters.""" mcp = FastMCP() @mcp.resource("math://add/{x}") 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() @mcp.resource("resource://{name}/data") 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() @mcp.resource("users://email/{email}") @mcp.resource("users://name/{name}") 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() @mcp.resource("resource://{param}", tags={"template", "test-tag"}) 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() @mcp.resource("resource://{param*}") 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() @mcp.resource("resource://{param*}") def template_resource(param: str) -> str: return f"Template resource 1: {param}" @mcp.resource("resource://{x}/{y}") 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() @mcp.resource("resource://{x}/{y}") def template_resource_with_params(x: str, y: str) -> str: return f"Template resource 1: {x}/{y}" @mcp.resource("resource://{param*}") 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() @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 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 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() @mcp.prompt() 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() @mcp.prompt(name="custom_name") 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() @mcp.prompt(description="A custom description") 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"): @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}! {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() @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) == 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() @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[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() @mcp.prompt() 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() @mcp.resource("resource://data", tags={"example", "test-tag"}) 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() @mcp.resource("resource://{param}", tags={"template", "test-tag"}) 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() @mcp.prompt(tags={"example", "test-tag"}) 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"}