create_bucket · Rustfs MCP: Risk & Policy

WHAT IT DOES

What create_bucket does on Rustfs

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

WHY IT NEEDS A POLICY

Why create_bucket needs a policy

This tool creates new S3 buckets, which is a write operation that modifies cloud infrastructure state. While creation is reversible (via delete_bucket), the act of creating infrastructure resources has a moderate blast radius if misused by an AI agent—it could consume quota, incur costs, or create unintended storage resources.

From the tool's definition Tool name is 'create_bucket' and description states 'Create a new bucket', indicating irreversible creation of cloud storage resources. The caveat '(Refused on read-only / production add-ons)' confirms it modifies state.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_bucket Rate-limited

create_bucket 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": {
    "create_bucket": {
      "limits": [
        {
          "counter": "create_bucket_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 Rustfs, so you can run agents against it safely.

FAQ

Questions about create_bucket

What does the create_bucket tool do? +

Create a new bucket. (Refused on read-only / production add-ons.). It is categorised as a Write tool in the Rustfs MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create_bucket? +

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

What risk level is create_bucket? +

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

Can I rate-limit create_bucket? +

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

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

create_bucket is provided by the Rustfs MCP server (stackblaze/rustfs-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.