update-script · Mcp Dev MCP: Risk & Policy

WHAT IT DOES

What update-script does on Mcp Dev

AI agents use update-script 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-script needs a policy

The tool modifies (not deletes) script files, placing it in Write category. Severity is high because updating scripts in a CMS can have broad runtime consequences—malicious script changes could compromise site functionality, inject malicious code, or alter business logic. However, it is reversible (scripts can be updated again), so it does not reach Destructive or Execute severity.

From the tool's definition Tool name 'update-script' and description 'Updates a script by path' indicate modification of script files, which are executable code artifacts in a CMS environment.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update-script Rate-limited

update-script 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-script": {
      "limits": [
        {
          "counter": "update-script_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-script

What does the update-script tool do? +

Updates a script 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-script? +

Register the Mcp Dev MCP server in PolicyLayer and add a rule for update-script: 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-script? +

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

Can I rate-limit update-script? +

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

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

update-script 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.