feat(MCP): MCP refactor, support stdio, and running MCP server in runtime (#7911)

Co-authored-by: openhands <openhands@all-hands.dev>
Co-authored-by: Calvin Smith <email@cjsmith.io>

tests/runtime/test_mcp_action.py

@@ -0,0 +1,78 @@
+"""Bash-related tests for the DockerRuntime, which connects to the ActionExecutor running in the sandbox."""
+
+import json
+import os
+
+import pytest
+from conftest import (
+    _load_runtime,
+)
+
+import openhands
+from openhands.core.config import MCPConfig
+from openhands.core.config.mcp_config import MCPStdioServerConfig
+from openhands.core.logger import openhands_logger as logger
+from openhands.events.action import CmdRunAction, MCPAction
+from openhands.events.observation import CmdOutputObservation, MCPObservation
+
+# ============================================================================================================================
+# Bash-specific tests
+# ============================================================================================================================
+
+
+def test_default_activated_tools():
+    project_root = os.path.dirname(openhands.__file__)
+    mcp_config_path = os.path.join(project_root, 'runtime', 'mcp', 'config.json')
+    assert os.path.exists(
+        mcp_config_path
+    ), f'MCP config file not found at {mcp_config_path}'
+    with open(mcp_config_path, 'r') as f:
+        mcp_config = json.load(f)
+    assert 'default' in mcp_config
+    # no tools are always activated yet
+    assert len(mcp_config['default']) == 0
+
+
+@pytest.mark.asyncio
+async def test_fetch_mcp_via_stdio(temp_dir, runtime_cls, run_as_openhands):
+    mcp_stdio_server_config = MCPStdioServerConfig(
+        name='fetch', command='uvx', args=['mcp-server-fetch']
+    )
+    override_mcp_config = MCPConfig(stdio_servers=[mcp_stdio_server_config])
+    runtime, config = _load_runtime(
+        temp_dir, runtime_cls, run_as_openhands, override_mcp_config=override_mcp_config
+    )
+
+    # Test browser server
+    action_cmd = CmdRunAction(command='python3 -m http.server 8000 > server.log 2>&1 &')
+    logger.info(action_cmd, extra={'msg_type': 'ACTION'})
+    obs = runtime.run_action(action_cmd)
+    logger.info(obs, extra={'msg_type': 'OBSERVATION'})
+
+    assert isinstance(obs, CmdOutputObservation)
+    assert obs.exit_code == 0
+    assert '[1]' in obs.content
+
+    action_cmd = CmdRunAction(command='sleep 3 && cat server.log')
+    logger.info(action_cmd, extra={'msg_type': 'ACTION'})
+    obs = runtime.run_action(action_cmd)
+    logger.info(obs, extra={'msg_type': 'OBSERVATION'})
+    assert obs.exit_code == 0
+
+    mcp_action = MCPAction(name='fetch', arguments={'url': 'http://localhost:8000'})
+    obs = await runtime.call_tool_mcp(mcp_action)
+    logger.info(obs, extra={'msg_type': 'OBSERVATION'})
+    assert isinstance(
+        obs, MCPObservation
+    ), 'The observation should be a MCPObservation.'
+
+    result_json = json.loads(obs.content)
+    assert not result_json['isError']
+    assert len(result_json['content']) == 1
+    assert result_json['content'][0]['type'] == 'text'
+    assert (
+        result_json['content'][0]['text']
+        == 'Contents of http://localhost:8000/:\n---\n\n* <server.log>\n\n---'
+    )
+
+    runtime.close()