AI agents call gem-list to retrieve information from Python without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and retrieves package metadata (installed Ruby gems and their versions) without any side effects. It performs a read-only inspection of the system state, similar to running 'gem list' locally. There is no risk of data modification, code execution, or resource consumption beyond the query itself. The low severity reflects minimal blast radius if misused by an AI agent.
From the tool's definition Tool description states it 'Lists installed Ruby gems' and 'Returns structured JSON' — a purely informational operation with no modification, deletion, or execution of code.
Attacks that exploit this kind of access
Lists installed Ruby gems with version information. Returns structured JSON with gem names and versions. It is categorised as a Read tool in the Python MCP Server, which means it retrieves data without modifying state.
Register the Python MCP server in PolicyLayer and add a rule for gem-list: 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. Nothing to install.
gem-list 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 gem-list 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 gem-list. 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.
gem-list is provided by the Python MCP server (Dave-London/Pare). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
gem-list is one line of Python'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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