update_url · YOURLS- MCP: Risk & Policy

WHAT IT DOES

What update_url does on YOURLS-MCP

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

WHY IT NEEDS A POLICY

Why update_url needs a policy

This tool modifies an existing short URL's destination, changing where it redirects. While reversible (can be updated again), it affects the behavior of an active short link that may be in circulation, potentially redirecting users to unintended destinations.

From the tool's definition Tool description states 'Update an existing short URL to point to a different destination URL', which modifies existing data. The name 'update_url' confirms this is a modification operation rather than retrieval or deletion.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_url Rate-limited

update_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": {
    "update_url": {
      "limits": [
        {
          "counter": "update_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 YOURLS-MCP, so you can run agents against it safely.

FAQ

Questions about update_url

What does the update_url tool do? +

Update an existing short URL to point to a different destination URL. It is categorised as a Write tool in the YOURLS-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 update_url? +

Register the YOURLS- MCP server in PolicyLayer and add a rule for update_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 YOURLS-MCP. Nothing to install.

What risk level is update_url? +

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

Can I rate-limit update_url? +

Yes. Add a rate_limit block to the update_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 update_url completely? +

Set action: deny in the PolicyLayer policy for update_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 update_url? +

update_url is provided by the YOURLS- MCP server (kesslerio/yourls-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

// THE FULL RECORD

update_url is one line of YOURLS-'s registry record.

The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.

Teams ship this data inside their own products. See what a licence covers →