# server.py
import sys
import io
import contextlib
from mcp.server.fastmcp import FastMCP

mcp = FastMCP("Sandbox-Python")

@mcp.tool()
def execute_python_code(code: str) -> str:
    """
    Executes arbitrary Python 3 code in this isolated sandbox container.
    Returns the standard output (stdout) and error streams (stderr).
    """
    stdout_buffer = io.StringIO()
    stderr_buffer = io.StringIO()
    
    with contextlib.redirect_stdout(stdout_buffer), contextlib.redirect_stderr(stderr_buffer):
        try:
            # Execute within isolated global/local frames
            exec(code, {}, {})
        except Exception as e:
            sys.stderr.write(f"Runtime Error: {str(e)}")
            
    output = stdout_buffer.getvalue()
    errors = stderr_buffer.getvalue()
    
    if errors:
        return f"Errors caught during execution:\n{errors}\nPartial Output:\n{output}"
    return output if output else "Code executed successfully with no returned stdout."

if __name__ == "__main__":
    # Override standard stdio pipes to expose an HTTP/SSE server
    mcp.run(transport="sse", host="0.0.0.0", port=8000)