update-stylesheet · Mcp Dev MCP: Risk & Policy

WHAT IT DOES

What update-stylesheet does on Mcp Dev

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

WHY IT NEEDS A POLICY

Why update-stylesheet needs a policy

This tool modifies stylesheets in an Umbraco CMS system, which is a reversible Write operation. The modification affects presentation layer files but is not destructive (can be reverted) and has bounded scope to a single stylesheet. Severity is medium due to potential impact on site appearance/functionality if modified incorrectly, but limited to CSS styling artifacts rather than core data or financial systems.

From the tool's definition Tool name explicitly states 'update-stylesheet' and description confirms it 'Updates a stylesheet by path', indicating modification of existing data.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update-stylesheet Rate-limited

update-stylesheet 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-stylesheet": {
      "limits": [
        {
          "counter": "update-stylesheet_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 Dev, so you can run agents against it safely.

FAQ

Questions about update-stylesheet

What does the update-stylesheet tool do? +

Updates a stylesheet by path. It is categorised as a Write tool in the Mcp Dev 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-stylesheet? +

Register the Mcp Dev MCP server in PolicyLayer and add a rule for update-stylesheet: 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 Dev. Nothing to install.

What risk level is update-stylesheet? +

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

Can I rate-limit update-stylesheet? +

Yes. Add a rate_limit block to the update-stylesheet 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-stylesheet completely? +

Set action: deny in the PolicyLayer policy for update-stylesheet. 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-stylesheet? +

update-stylesheet is provided by the Mcp Dev MCP server (@umbraco-cms/mcp-dev). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.