copy_object · S3 MCP: Risk & Policy

WHAT IT DOES

What copy_object does on S3

AI agents use copy_object to create or update resources in S3 — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your S3 environment.

WHY IT NEEDS A POLICY

Why copy_object needs a policy

Copying an S3 object is a reversible write operation—it creates or duplicates data without irreversibly deleting or overwriting existing data. While the description is empty, the tool name combined with the S3 server context and presence of sibling destructive/write tools clearly indicates object duplication capability.

From the tool's definition Tool name is 'copy_object' in an AWS S3 MCP server context alongside destructive operations (delete_object, delete_objects) and write operations (put_object, upload_file).

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 S3, so you can run agents against it safely.

FAQ

Questions about copy_object

What does the copy_object tool do? +

copy_object. It is categorised as a Write tool in the S3 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 S3 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 S3. 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 S3 MCP server (konmam/s3-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.