Add context injection to all objects

src/fastmcp/resources/resource_manager.py

@@ -61,9 +61,16 @@ class ResourceManager:
             The added resource or template. If a resource or template with the same URI already exists,
             returns the existing resource or template.
         """
+        from fastmcp.server.context import Context
+
         # Check if this should be a template
         has_uri_params = "{" in uri and "}" in uri
-        has_func_params = bool(inspect.signature(fn).parameters)
+        # check if the function has any parameters (other than injected context)
+        has_func_params = any(
+            p
+            for p in inspect.signature(fn).parameters.values()
+            if p.annotation is not Context
+        )
 
         if has_uri_params or has_func_params:
             return self.add_template_from_fn(
@@ -102,12 +109,12 @@ class ResourceManager:
             The added resource. If a resource with the same URI already exists,
             returns the existing resource.
         """
-        resource = FunctionResource(
+        resource = FunctionResource.from_function(
+            fn=fn,
             uri=AnyUrl(uri),
             name=name,
             description=description,
             mime_type=mime_type or "text/plain",
-            fn=fn,
             tags=tags or set(),
         )
         return self.add_resource(resource)
@@ -235,7 +242,9 @@ class ResourceManager:
             if params := match_uri_template(uri_str, storage_key):
                 try:
                     return await template.create_resource(
-                        uri_str, params, context=context
+                        uri_str,
+                        params=params,
+                        context=context,
                     )
                 except Exception as e:
                     raise ValueError(f"Error creating resource from template: {e}")

src/fastmcp/resources/template.py

@@ -189,7 +189,7 @@ class ResourceTemplate(BaseModel):
                 name=self.name,
                 description=self.description,
                 mime_type=self.mime_type,
-                fn=lambda: result,  # Capture result in closure
+                fn=lambda **kwargs: result,  # Capture result in closure
                 tags=self.tags,
                 context_kwarg=self.context_kwarg,
             )

src/fastmcp/resources/types.py

@@ -15,6 +15,7 @@ import pydantic.json
 import pydantic_core
 from pydantic import Field, ValidationInfo
 
+import fastmcp
 from fastmcp.resources.resource import Resource
 
 if TYPE_CHECKING:
@@ -66,8 +67,23 @@ class FunctionResource(Resource):
         default=None, description="Name of the kwarg that should receive context"
     )
 
+    @classmethod
+    def from_function(
+        cls, fn: Callable[[], Any], context_kwarg: str | None = None, **kwargs
+    ) -> FunctionResource:
+        if context_kwarg is None:
+            parameters = inspect.signature(fn).parameters
+            context_param = next(
+                (p for p in parameters.values() if p.annotation is fastmcp.Context),
+                None,
+            )
+            if context_param is not None:
+                context_kwarg = context_param.name
+        return cls(fn=fn, context_kwarg=context_kwarg, **kwargs)
+
     async def read(
-        self, context: Context[ServerSessionT, LifespanContextT] | None = None
+        self,
+        context: Context[ServerSessionT, LifespanContextT] | None = None,
     ) -> str | bytes:
         """Read the resource by calling the wrapped function."""
         try:
@@ -80,7 +96,7 @@ class FunctionResource(Resource):
                 result = await result
 
             if isinstance(result, Resource):
-                return await result.read()
+                return await result.read(context=context)
             if isinstance(result, bytes):
                 return result
             if isinstance(result, str):
@@ -127,7 +143,9 @@ class FileResource(Resource):
         mime_type = info.data.get("mime_type", "text/plain")
         return not mime_type.startswith("text/")
 
-    async def read(self) -> str | bytes:
+    async def read(
+        self, context: Context[ServerSessionT, LifespanContextT] | None = None
+    ) -> str | bytes:
         """Read the file content."""
         try:
             if self.is_binary:
@@ -145,7 +163,9 @@ class HttpResource(Resource):
         default="application/json", description="MIME type of the resource content"
     )
 
-    async def read(self) -> str | bytes:
+    async def read(
+        self, context: Context[ServerSessionT, LifespanContextT] | None = None
+    ) -> str | bytes:
         """Read the HTTP content."""
         async with httpx.AsyncClient() as client:
             response = await client.get(self.url)
@@ -197,7 +217,9 @@ class DirectoryResource(Resource):
         except Exception as e:
             raise ValueError(f"Error listing directory {self.path}: {e}")
 
-    async def read(self) -> str:  # Always returns JSON string
+    async def read(
+        self, context: Context[ServerSessionT, LifespanContextT] | None = None
+    ) -> str:  # Always returns JSON string
         """Read the directory listing."""
         try:
             files = await anyio.to_thread.run_sync(self.list_files)

src/fastmcp/server/openapi.py

@@ -265,7 +265,9 @@ class OpenAPIResource(Resource):
         self._client = client
         self._route = route
 
-    async def read(self) -> str | bytes:
+    async def read(
+        self, context: Context[ServerSessionT, LifespanContextT] | None = None
+    ) -> str | bytes:
         """Fetch the resource data by making an HTTP request."""
         try:
             # Extract path parameters from the URI if present

src/fastmcp/server/server.py

@@ -401,7 +401,7 @@ class FastMCP(Generic[LifespanResultT]):
             context = self.get_context()
             resource = await self._resource_manager.get_resource(uri, context=context)
             try:
-                content = await resource.read()
+                content = await resource.read(context=context)
                 return [
                     ReadResourceContents(content=content, mime_type=resource.mime_type)
                 ]
@@ -427,7 +427,7 @@ class FastMCP(Generic[LifespanResultT]):
         if self._prompt_manager.has_prompt(name):
             context = self.get_context()
             messages = await self._prompt_manager.render_prompt(
-                name, arguments, context=context
+                name, arguments=arguments or {}, context=context
             )
             return GetPromptResult(messages=pydantic_core.to_jsonable_python(messages))
         else:

tests/server/test_server_interactions.py

@@ -682,7 +682,147 @@ class TestToolParameters:
             assert result[0].text == "0:16:40"
 
 
-class TestResources:
+class TestToolContextInjection:
+    """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()
+
+        @mcp.tool()
+        def tool_with_context(x: int, ctx: Context) -> str:
+            assert isinstance(ctx, Context)
+            assert ctx.request_id is not None
+            return ctx.request_id
+
+        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 content.text == "1"
+
+    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 TestResource:
     async def test_text_resource(self):
         mcp = FastMCP()
 
@@ -756,6 +896,21 @@ class TestResources:
             assert result[0].blob == base64.b64encode(b"Binary file data").decode()
 
 
+class TestResourceContext:
+    async def test_resource_with_context_annotation_gets_context(self):
+        mcp = FastMCP()
+
+        @mcp.resource("resource://test")
+        def resource_with_context(ctx: Context) -> str:
+            assert isinstance(ctx, Context)
+            return ctx.request_id
+
+        async with Client(mcp) as client:
+            result = await client.read_resource(AnyUrl("resource://test"))
+            assert isinstance(result[0], TextResourceContents)
+            assert result[0].text == "1"
+
+
 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
@@ -1026,144 +1181,19 @@ class TestResourceTemplates:
             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."""
+class TestResourceTemplateContext:
+    async def test_resource_template_context(self):
         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}"
+        @mcp.resource("resource://{param}")
+        def resource_template(param: str, ctx: Context) -> str:
+            assert isinstance(ctx, Context)
+            return f"Resource template: {param} {ctx.request_id}"
 
         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
+            result = await client.read_resource(AnyUrl("resource://test"))
+            assert isinstance(result[0], TextResourceContents)
+            assert result[0].text == "Resource template: test 1"
 
 
 class TestPrompts:
@@ -1350,3 +1380,19 @@ class TestPrompts:
         assert len(prompts_dict) == 1
         prompt = prompts_dict["sample_prompt"]
         assert prompt.tags == {"example", "test-tag"}
+
+
+class TestPromptContext:
+    async def test_prompt_context(self):
+        mcp = FastMCP()
+
+        @mcp.prompt()
+        def prompt_fn(name: str, ctx: Context) -> str:
+            assert isinstance(ctx, Context)
+            return f"Hello, {name}! {ctx.request_id}"
+
+        async with Client(mcp) as client:
+            result = await client.get_prompt("prompt_fn", {"name": "World"})
+            assert len(result) == 1
+            message = result[0]
+            assert message.role == "user"