AI agents call list_session_variables to retrieve information from MCP Mathematics without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and displays session variables without side effects. It performs a simple read operation consistent with query/list/get patterns. No data is modified, deleted, or executed. Severity is low because session variables in a math computation context pose minimal risk even if exposed to an AI agent.
From the tool's definition Tool name 'list_session_variables' and description 'List session variables' indicate a retrieval operation that queries and displays existing session data without modification, deletion, or execution of code.
Documented attack patterns abuse exactly the kind of access list_session_variables gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MCP Mathematics, and nothing reaches the server without passing your rules. This is the rule we recommend for list_session_variables:
{
"version": "1",
"default": "deny",
"tools": {
"list_session_variables": {}
}
}list_session_variables is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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List session variables. It is categorised as a Read tool in the MCP Mathematics MCP Server, which means it retrieves data without modifying state.
Register the MCP Mathematics MCP server in PolicyLayer and add a rule for list_session_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 MCP Mathematics. Nothing to install.
list_session_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_session_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_session_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_session_variables is provided by the MCP Mathematics MCP server (shsharkar/mcp-mathematics). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from MCP Mathematics, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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18 MCP Mathematics tools catalogued and risk-classified — across an index of 43,000+ MCP servers.