Expand a shortened URL to get the original URL
AI agents call expand_url to retrieve information from LinkShrink MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The expand_url tool retrieves the original URL associated with a shortened link. This is a pure read operation: it queries data (the mapping between short and long URLs) and returns it without creating, modifying, or deleting anything. There are no side effects, no execution of external operations, and no destructive or financial implications.
From the tool's definition Tool description states 'Expand a shortened URL to get the original URL' — a retrieval operation that returns data without modification or side effects.
Attacks that exploit this kind of access
Expand a shortened URL to get the original URL. It is categorised as a Read tool in the LinkShrink MCP MCP Server, which means it retrieves data without modifying state.
Register the LinkShrink MCP server in PolicyLayer and add a rule for expand_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 LinkShrink MCP. Nothing to install.
expand_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 expand_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 expand_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.
expand_url is provided by the LinkShrink MCP server (linkshrink-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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