AI agents call list_tools to retrieve information from Mcp Proxy without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a retrieval operation that queries and returns information about available tools. It has no side effects, does not execute code, does not modify data, and does not delete anything. It is a straightforward informational read operation, making it low severity even in a misuse scenario where an agent might list tools repeatedly.
From the tool's definition Tool name 'list_tools' and description 'List tools available on a server. Returns names and short descriptions only' indicate a query operation that retrieves metadata about available tools without modifying or executing anything.
Attacks that exploit this kind of access
List tools available on a server. Returns names and short descriptions only. It is categorised as a Read tool in the Mcp Proxy MCP Server, which means it retrieves data without modifying state.
Register the Mcp Proxy MCP server in PolicyLayer and add a rule for list_tools: 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 Proxy. Nothing to install.
list_tools 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_tools 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_tools. 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_tools is provided by the Mcp Proxy MCP server (shengxiao20/mcp-proxy-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
list_tools is one line of Mcp Proxy'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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