AI agents call yfy_get_download_url to retrieve information from Yifangyun 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 a download URL, which is a read-only operation that retrieves information with no side effects. It does not download content, modify data, execute code, or make financial transactions. The pre-signed URL is simply metadata for potential access. The explicit note that the server never logs the URL further confirms this is a retrieval operation.
From the tool's definition Tool description states 'Get a pre-signed download URL for a file' and 'The server never downloads the file content and never logs the URL.' The tool retrieves a URL for access purposes without actually transferring data or modifying any state.
Attacks that exploit this kind of access
Get a pre-signed download URL for a file. The server never downloads the file content and never logs the URL. It is categorised as a Read tool in the Yifangyun MCP Server, which means it retrieves data without modifying state.
Register the Yifangyun MCP server in PolicyLayer and add a rule for yfy_get_download_url: 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 Yifangyun. Nothing to install.
yfy_get_download_url 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 yfy_get_download_url 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 yfy_get_download_url. 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.
yfy_get_download_url is provided by the Yifangyun MCP server (mrhegit/yifangyun-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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