create-temporary-file · Mcp Dev MCP: Risk & Policy

WHAT IT DOES

What create-temporary-file does on Mcp Dev

AI agents use create-temporary-file 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 create-temporary-file needs a policy

This tool creates temporary files within Umbraco's system, which is a write operation that modifies system state by adding new resources. While the files auto-delete after 10 minutes, they are created and stored during that window, making this reversible (auto-deletion handles cleanup).

From the tool's definition "Creates a new temporary file" - creates data that persists for 10 minutes; "Provide the file content as a base64 encoded string" indicates the tool accepts and stores file content.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create-temporary-file Rate-limited

create-temporary-file 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": {
    "create-temporary-file": {
      "limits": [
        {
          "counter": "create-temporary-file_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 create-temporary-file

What does the create-temporary-file tool do? +

Creates a new temporary file. The file will be deleted after 10 minutes. The temporary file id is used when uploading media files to Umbraco. The process is as follows: - Create a temporary file using this endpoint - Use the temporary file id when creating a media item using the media post endpoint Provide the file content as a base64 encoded string. 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 create-temporary-file? +

Register the Mcp Dev MCP server in PolicyLayer and add a rule for create-temporary-file: 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 create-temporary-file? +

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

Can I rate-limit create-temporary-file? +

Yes. Add a rate_limit block to the create-temporary-file 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 create-temporary-file completely? +

Set action: deny in the PolicyLayer policy for create-temporary-file. 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 create-temporary-file? +

create-temporary-file 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.