AI agents call list_rois to retrieve information from Millimap 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 regions of interest (ROIs) from an active MilliMap session. The verb 'list' and the lack of any indication of modification, deletion, or execution means this is a read-only operation.
From the tool's definition Tool name 'list_rois' and description 'List all ROIs saved in the current MilliMap session' indicate a query/retrieval operation with no side effects.
Attacks that exploit this kind of access
List all ROIs saved in the current MilliMap session. It is categorised as a Read tool in the Millimap MCP Server, which means it retrieves data without modifying state.
Register the Millimap MCP server in PolicyLayer and add a rule for list_rois: 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 Millimap. Nothing to install.
list_rois 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_rois 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_rois. 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_rois is provided by the Millimap MCP server (milliomics/millimap-mcp). 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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