shelby_upload · Shelby MCP: Risk & Policy

WHAT IT DOES

What shelby_upload does on Shelby

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

WHY IT NEEDS A POLICY

Why shelby_upload needs a policy

The shelby_upload tool creates and writes data to decentralized storage (Aptos), which is a reversible operation. It does not execute code, delete data, or move funds, so it falls under Write category.

From the tool's definition Tool description states 'Upload a file to Shelby decentralized storage' with parameters for file content, destination blob name, and expiration. This creates new data on decentralized storage.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

shelby_upload Rate-limited

shelby_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": {
    "shelby_upload": {
      "limits": [
        {
          "counter": "shelby_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 Shelby, so you can run agents against it safely.

FAQ

Questions about shelby_upload

What does the shelby_upload tool do? +

Upload a file to Shelby decentralized storage. Provide file content as text, a destination blob name, and expiration. It is categorised as a Write tool in the Shelby MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on shelby_upload? +

Register the Shelby MCP server in PolicyLayer and add a rule for shelby_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 Shelby. Nothing to install.

What risk level is shelby_upload? +

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

Can I rate-limit shelby_upload? +

Yes. Add a rate_limit block to the shelby_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 shelby_upload completely? +

Set action: deny in the PolicyLayer policy for shelby_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 shelby_upload? +

shelby_upload is provided by the Shelby MCP server (jasekeee/shelby-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.