shorten_url · LinkShrink MCP: Risk & Policy

WHAT IT DOES

What shorten_url does on LinkShrink MCP

AI agents use shorten_url to create or update resources in LinkShrink MCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your LinkShrink MCP environment.

WHY IT NEEDS A POLICY

Why shorten_url needs a policy

The tool creates a new resource (a short URL entry) in the system. This is a Write operation as it modifies state by adding a new URL mapping. It is not Destructive, Financial, or Execute. Severity is low because misuse at worst creates unwanted short URL entries with minimal blast radius.

From the tool's definition 'Shorten a URL with optional custom alias. Returns a short URL.' — creates a new shortened URL mapping, which is a reversible write operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

shorten_url Rate-limited

shorten_url stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "shorten_url": {
      "limits": [
        {
          "counter": "shorten_url_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches LinkShrink MCP, so you can run agents against it safely.

FAQ

Questions about shorten_url

What does the shorten_url tool do? +

Shorten a URL with optional custom alias. Returns a short URL. It is categorised as a Write tool in the LinkShrink MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on shorten_url? +

Register the LinkShrink MCP server in PolicyLayer and add a rule for shorten_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.

What risk level is shorten_url? +

shorten_url is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit shorten_url? +

Yes. Add a rate_limit block to the shorten_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.

How do I block shorten_url completely? +

Set action: deny in the PolicyLayer policy for shorten_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.

What MCP server provides shorten_url? +

shorten_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.