feat: add MCP Resources support

Author: MuhammadHassaanArain

pyproject.toml

@@ -77,7 +77,10 @@ dev = [
 ]
 
 [tool.uv.workspace]
-members = ["agents"]
+members = [
+    "agents",
+    "checking",
+]
 
 [tool.uv.sources]
 agents = { workspace = true }

src/agents/mcp/server.py

@@ -7,15 +7,16 @@
 from contextlib import AbstractAsyncContextManager, AsyncExitStack
 from datetime import timedelta
 from pathlib import Path
-from typing import TYPE_CHECKING, Any, Callable, Literal, TypeVar
+from typing import TYPE_CHECKING, Any, Callable, Literal, TypeVar, AsyncIterator
+
 
 from anyio.streams.memory import MemoryObjectReceiveStream, MemoryObjectSendStream
 from mcp import ClientSession, StdioServerParameters, Tool as MCPTool, stdio_client
 from mcp.client.session import MessageHandlerFnT
 from mcp.client.sse import sse_client
 from mcp.client.streamable_http import GetSessionIdCallback, streamablehttp_client
 from mcp.shared.message import SessionMessage
-from mcp.types import CallToolResult, GetPromptResult, InitializeResult, ListPromptsResult
+from mcp.types import CallToolResult, GetPromptResult, InitializeResult, ListPromptsResult, ListResourcesResult, ReadResourceResult
 from typing_extensions import NotRequired, TypedDict
 
 from ..exceptions import UserError
@@ -78,6 +79,19 @@ async def call_tool(self, tool_name: str, arguments: dict[str, Any] | None) -> C
         """Invoke a tool on the server."""
         pass
 
+    @abc.abstractmethod
+    async def list_resources(self)-> ListResourcesResult:
+        """List resources available on the server."""
+        pass
+    @abc.abstractmethod
+    async def read_resource(self, uri:str)-> ReadResourceResult:
+        """Read the content of a resource by URI."""
+        pass
+    @abc.abstractmethod
+    async def subscribe_resource(self, uri:str, **kwargs) -> AsyncIterator[SessionMessage]:
+        """Subscribe to resource updates."""
+        pass
+
     @abc.abstractmethod
     async def list_prompts(
         self,
@@ -91,7 +105,7 @@ async def get_prompt(
     ) -> GetPromptResult:
         """Get a specific prompt from the server."""
         pass
-
+    
 
 class _MCPServerWithClientSession(MCPServer, abc.ABC):
     """Base class for MCP servers that use a `ClientSession` to communicate with the server."""
@@ -140,7 +154,6 @@ def __init__(
         self.max_retry_attempts = max_retry_attempts
         self.retry_backoff_seconds_base = retry_backoff_seconds_base
         self.message_handler = message_handler
-
         # The cache is always dirty at startup, so that we fetch tools at least once
         self._cache_dirty = True
         self._tools_list: list[MCPTool] | None = None
@@ -288,6 +301,10 @@ async def connect(self):
             await self.cleanup()
             raise
 
+
+
+
+
     async def list_tools(
         self,
         run_context: RunContextWrapper[Any] | None = None,
@@ -326,6 +343,30 @@ async def call_tool(self, tool_name: str, arguments: dict[str, Any] | None) -> C
 
         return await self._run_with_retries(lambda: session.call_tool(tool_name, arguments))
 
+    async def list_resources(self)-> ListResourcesResult:
+        if not self.session:
+            raise UserError("Server not initialized. Make sure you call `connect()` first.")
+        session = self.session
+        assert session is not None
+        return await session.list_resources()
+        
+    async def read_resource(self,uri:str)-> ReadResourceResult:
+        if not self.session:
+            raise UserError("Server not initialized. Make sure you call `connect()` first.")
+        session = self.session
+        assert session is not None
+        return await session.read_resource(uri)
+    
+    async def subscribe_resource(self, uri:str, **kwargs)-> AsyncIterator[SessionMessage]:
+        if not self.session:
+            raise UserError("Server not initialized. Make sure you call `connect()` first.")
+        session = self.session
+        assert session is not None
+        async for msg in session.subscribe_resource(uri, **kwargs):
+            yield msg
+        
+
+
     async def list_prompts(
         self,
     ) -> ListPromptsResult:
@@ -593,6 +634,8 @@ class MCPServerStreamableHttpParams(TypedDict):
     """Custom HTTP client factory for configuring httpx.AsyncClient behavior."""
 
 
+
+
 class MCPServerStreamableHttp(_MCPServerWithClientSession):
     """MCP server implementation that uses the Streamable HTTP transport. See the [spec]
     (https://modelcontextprotocol.io/specification/2025-03-26/basic/transports#streamable-http)
@@ -688,4 +731,4 @@ def create_streams(
     @property
     def name(self) -> str:
         """A readable name for the server."""
-        return self._name
+        return self._name