get_upload_url · Publora MCP Server MCP: Risk & Policy

WHAT IT DOES

What get_upload_url does on Publora MCP Server

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

WHY IT NEEDS A POLICY

Why get_upload_url needs a policy

This tool generates a presigned S3 URL intended for uploading media content. While the tool itself only retrieves a URL, its explicit purpose is to enable a write operation (media upload to S3). The net effect is facilitating content creation/modification on cloud storage. Classified as Write since the URL generation is a reversible, upload-enabling action.

From the tool's definition Get a presigned S3 URL to upload media (image/video) for a post

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

get_upload_url Rate-limited

get_upload_url 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": {
    "get_upload_url": {
      "limits": [
        {
          "counter": "get_upload_url_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Publora MCP Server, so you can run agents against it safely.

FAQ

Questions about get_upload_url

What does the get_upload_url tool do? +

Get a presigned S3 URL to upload media (image/video) for a post. It is categorised as a Write tool in the Publora 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 get_upload_url? +

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

What risk level is get_upload_url? +

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

Can I rate-limit get_upload_url? +

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

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

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