upload-media · Sync MCP Server MCP: Risk & Policy

WHAT IT DOES

What upload-media does on Sync MCP Server

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

WHY IT NEEDS A POLICY

Why upload-media needs a policy

This tool creates new records (uploaded media assets) in a persistent storage system and returns identifiers for later reference. It is reversible (files can be deleted), so it is Write rather than Destructive.

From the tool's definition Tool description states it will 'Upload a user-provided image, video, or audio file to Sync asset storage and return a durable assetId.' The verb 'Upload' and action of storing files in asset storage indicates data creation/modification.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

upload-media Rate-limited

upload-media 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": {
    "upload-media": {
      "limits": [
        {
          "counter": "upload-media_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 Sync MCP Server, so you can run agents against it safely.

FAQ

Questions about upload-media

What does the upload-media tool do? +

Upload a user-provided image, video, or audio file to Sync asset storage and return a durable assetId. It is categorised as a Write tool in the Sync 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 upload-media? +

Register the Sync MCP Server MCP server in PolicyLayer and add a rule for upload-media: 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 Sync MCP Server. Nothing to install.

What risk level is upload-media? +

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

Can I rate-limit upload-media? +

Yes. Add a rate_limit block to the upload-media 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 upload-media completely? +

Set action: deny in the PolicyLayer policy for upload-media. 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 upload-media? +

upload-media is provided by the Sync MCP Server MCP server (synchronicity-labs/mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.