jupyter_list_variables
AI agents call jupyter_list_variables to retrieve information from ML Jupyter MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries the current set of variables and their values in the Jupyter kernel's memory—a read-only operation with no side effects. Even though the description is empty, the name strongly indicates data retrieval rather than mutation or execution.
From the tool's definition Tool name 'jupyter_list_variables' indicates retrieval/querying of variable state in the Jupyter kernel. Server description confirms persistent state management. No modification, deletion, or code execution implied by the name.
Attacks that exploit this kind of access
jupyter_list_variables. It is categorised as a Read tool in the ML Jupyter MCP MCP Server, which means it retrieves data without modifying state.
Register the ML Jupyter MCP server in PolicyLayer and add a rule for jupyter_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 ML Jupyter MCP. Nothing to install.
jupyter_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 jupyter_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 jupyter_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.
jupyter_list_variables is provided by the ML Jupyter MCP server (mayank-ketkar-sf/claudejupy). 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.
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