AI agents call list_sessions to retrieve information from Zmachine without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and returns metadata about active Z-Machine game sessions. It is purely informational and does not create, modify, delete, or execute any operations. The blast radius of misuse is negligible — an AI agent calling this repeatedly or without authorization would at worst enumerate sessions, which is a read-only disclosure concern rather than a critical risk.
From the tool's definition Tool name and description indicate it 'List[s] all currently active game sessions' — a retrieval operation with no side effects. No data modification, deletion, code execution, or financial implications.
Attacks that exploit this kind of access
List all currently active game sessions with their IDs, game, state, and status line. It is categorised as a Read tool in the Zmachine MCP Server, which means it retrieves data without modifying state.
Register the Zmachine MCP server in PolicyLayer and add a rule for list_sessions: 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 Zmachine. Nothing to install.
list_sessions 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_sessions 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_sessions. 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_sessions is provided by the Zmachine MCP server (jonathan-meyer/zmachine-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
list_sessions is one line of Zmachine's registry record.
The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.
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