PRIMS – Python Runtime Interpreter MCP Server

import asyncio import json from fastmcp import Client SERVER_URL = "http://localhost:9000/mcp" a_sync_code_first = """ import pandas as pd # Dataset was downloaded via `files` parameter. df = pd.read_csv('mounts/countries.csv') print("First 5 rows:\\n", df.head()) """ code_second = """ import pandas as pd df = pd.read_csv('mounts/countries.csv') print("Row count:", len(df)) """ async def main() -> None: """Demonstrate that files persist for the lifetime of an MCP session.""" async with Client("http://localhost:9000/mcp") as client: # 1. Run code that downloads a CSV file into the workspace mounts directory. first_params = { "code": a_sync_code_first, "files": [ { "url": "https://raw.githubusercontent.com/cs109/2014_data/master/countries.csv", "mountPath": "countries.csv", } ], } run1 = await client.call_tool("run_code", first_params) data1 = json.loads(run1[0].text) print("\n=== Run #1 ===") print("STDOUT:\n", data1.get("stdout")) print("STDERR:\n", data1.get("stderr")) print("ARTIFACTS:", data1.get("artifacts")) # 2. Execute a second snippet in the SAME client session. # We do NOT pass the `files` parameter again. The CSV should still exist. run2 = await client.call_tool("run_code", {"code": code_second}) data2 = json.loads(run2[0].text) print("\n=== Run #2 ===") print("STDOUT:\n", data2.get("stdout")) print("STDERR:\n", data2.get("stderr")) print("ARTIFACTS:", data2.get("artifacts")) if __name__ == "__main__": asyncio.run(main())