presign_image_upload · Rentalot MCP Server MCP

WHAT IT DOES

What presign_image_upload does on Rentalot MCP Server

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

WHY IT NEEDS A POLICY

Why presign_image_upload needs a policy

This tool creates and uploads new data (property images) to cloud storage, which is reversible (images can be deleted later). It does not execute arbitrary code, delete data, or move money. The requirement for 'Pro tier or higher' suggests access control exists but does not change the nature of the operation. Classified as Write rather than Read because it modifies system state by adding new assets.

From the tool's definition Tool description states 'Use to get a presigned URL for uploading a property image to R2 storage' and explicitly labels this as a 'Write operation.' The tool enables creation of new image assets in the system.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

presign_image_upload Rate-limited

presign_image_upload 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": {
    "presign_image_upload": {
      "limits": [
        {
          "counter": "presign_image_upload_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 Rentalot MCP Server, so you can run agents against it safely.

FAQ

Questions about presign_image_upload

What does the presign_image_upload tool do? +

Use to get a presigned URL for uploading a property image to R2 storage. Returns an upload URL and R2 key. Write operation — requires Pro tier or higher. It is categorised as a Write tool in the Rentalot MCP 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 presign_image_upload? +

Register the Rentalot MCP Server MCP server in PolicyLayer and add a rule for presign_image_upload: 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 Rentalot MCP Server. Nothing to install.

What risk level is presign_image_upload? +

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

Can I rate-limit presign_image_upload? +

Yes. Add a rate_limit block to the presign_image_upload 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 presign_image_upload completely? +

Set action: deny in the PolicyLayer policy for presign_image_upload. 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 presign_image_upload? +

presign_image_upload is provided by the Rentalot MCP Server MCP server (rentalot-ai/rentalot-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.