AI agents call pyodide_list-mounted-directory to retrieve information from Mcp Pyodide without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a directory listing operation, which is a non-destructive query of filesystem metadata. It retrieves information about files/folders in a mounted directory with no side effects, mutations, or external operations. It falls squarely into the Read category.
From the tool's definition Tool name contains 'list' and description explicitly states 'List contents of a mounted directory' — a read-only operation that retrieves directory contents without modification.
Documented attack patterns abuse exactly the kind of access pyodide_list-mounted-directory gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Mcp Pyodide, and nothing reaches the server without passing your rules. This is the rule we recommend for pyodide_list-mounted-directory:
{
"version": "1",
"default": "deny",
"tools": {
"pyodide_list-mounted-directory": {}
}
}pyodide_list-mounted-directory is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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List contents of a mounted directory. It is categorised as a Read tool in the Mcp Pyodide MCP Server, which means it retrieves data without modifying state.
Register the Mcp Pyodide MCP server in PolicyLayer and add a rule for pyodide_list-mounted-directory: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Mcp Pyodide. Nothing to install.
pyodide_list-mounted-directory is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the pyodide_list-mounted-directory rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for pyodide_list-mounted-directory. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
pyodide_list-mounted-directory is provided by the Mcp Pyodide MCP server (yonaka15/mcp-pyodide). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Mcp Pyodide, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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5 Mcp Pyodide tools catalogued and risk-classified — across an index of 43,000+ MCP servers.