feat: add MCP Resources support

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

@@ -3,7 +3,7 @@
 import abc
 import asyncio
 import inspect
-from collections.abc import Awaitable
+from collections.abc import AsyncIterator, Awaitable
 from contextlib import AbstractAsyncContextManager, AsyncExitStack
 from datetime import timedelta
 from pathlib import Path
@@ -15,7 +15,15 @@
 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 (
+    AnyUrl,
+    CallToolResult,
+    GetPromptResult,
+    InitializeResult,
+    ListPromptsResult,
+    ListResourcesResult,
+    ReadResourceResult,
+)
 from typing_extensions import NotRequired, TypedDict
 
 from ..exceptions import UserError
@@ -78,6 +86,21 @@ 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: AnyUrl) -> ReadResourceResult:
+        """Read the content of a resource by URI."""
+        pass
+
+    @abc.abstractmethod
+    async def subscribe_resource(self, uri: AnyUrl, **kwargs) -> AsyncIterator[SessionMessage]:
+        """Subscribe to resource updates."""
+        pass
+
     @abc.abstractmethod
     async def list_prompts(
         self,
@@ -140,7 +163,6 @@ 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
@@ -326,6 +348,28 @@ 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: AnyUrl) -> 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: AnyUrl, **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):
+            yield msg
+
     async def list_prompts(
         self,
     ) -> ListPromptsResult: