List all variables in the current session.
AI agents call list_variables to retrieve information from Python REPL MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves information about variables in memory—a read-only operation with no side effects. It does not create, modify, delete, or execute anything. The blast radius is minimal; misuse only exposes what variables exist in the session, which is informational. Severity is low because the scope is limited to inspection of the current REPL state.
From the tool's definition Tool name 'list_variables' and description 'List all variables in the current session' indicate a query operation that retrieves and displays data without modifying state or executing code.
Attacks that exploit this kind of access
List all variables in the current session. It is categorised as a Read tool in the Python REPL MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Python REPL MCP Server MCP server in PolicyLayer and add a rule for list_variables: 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 Python REPL MCP Server. Nothing to install.
list_variables 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 list_variables 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 list_variables. 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.
list_variables is provided by the Python REPL MCP Server MCP server (piplin-es/mcp-python). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
Teams ship this data inside their own products. See what a licence covers →