url-template · MCP QR Code Server MCP: Risk & Policy

WHAT IT DOES

What url-template does on MCP QR Code Server

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

WHY IT NEEDS A POLICY

Why url-template needs a policy

This is a Write operation because it creates/generates new QR code output. It does not read existing data (Read), execute arbitrary code (Execute), delete anything (Destructive), or move money (Financial). The severity is low because QR codes are passive artifacts—they only direct users to websites when scanned, with no autonomous side effects.

From the tool's definition The tool 'url-template' generates a QR code encoding a URL. The description states it will 'Generate a QR code that opens a website or web resource', which creates new data (the QR code artifact) without deletion or irreversible modification.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

url-template Rate-limited

url-template 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": {
    "url-template": {
      "limits": [
        {
          "counter": "url-template_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 MCP QR Code Server, so you can run agents against it safely.

FAQ

Questions about url-template

What does the url-template tool do? +

Generate a QR code that opens a website or web resource. It is categorised as a Write tool in the MCP QR Code Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on url-template? +

Register the MCP QR Code Server MCP server in PolicyLayer and add a rule for url-template: 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 QR Code Server. Nothing to install.

What risk level is url-template? +

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

Can I rate-limit url-template? +

Yes. Add a rate_limit block to the url-template 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 url-template completely? +

Set action: deny in the PolicyLayer policy for url-template. 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 url-template? +

url-template is provided by the MCP QR Code Server MCP server (jwalsh/mcp-server-qrcode). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.