copy_object · Storage MCP: Risk & Policy

WHAT IT DOES

What copy_object does on Storage

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

WHY IT NEEDS A POLICY

Why copy_object needs a policy

The copy_object tool creates or duplicates data within GCS buckets. This is a Write category action because it is reversible (the copied object can be deleted). It is not Execute (no arbitrary code run), not Destructive (copying does not delete originals), and not Financial.

From the tool's definition Tool description states it 'Copies an object from one bucket to another or within the same bucket.' Copy operations create new data or modify bucket contents, which is a reversible write action.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

copy_object Rate-limited

copy_object 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": {
    "copy_object": {
      "limits": [
        {
          "counter": "copy_object_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 Storage, so you can run agents against it safely.

FAQ

Questions about copy_object

What does the copy_object tool do? +

Copies an object from one bucket to another or within the same bucket. It is categorised as a Write tool in the Storage MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on copy_object? +

Register the Storage MCP server in PolicyLayer and add a rule for copy_object: 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 Storage. Nothing to install.

What risk level is copy_object? +

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

Can I rate-limit copy_object? +

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

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

copy_object is provided by the Storage MCP server (@google-cloud/storage-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.