put_object_text · Rustfs MCP: Risk & Policy

WHAT IT DOES

What put_object_text does on Rustfs

AI agents use put_object_text 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 put_object_text needs a policy

This tool creates or modifies objects in S3 storage, which is a reversible write operation. It does not delete data (Destructive), execute arbitrary code (Execute), move money (Financial), or merely query data (Read). The medium severity reflects that misuse could corrupt or overwrite important data in storage, but the operation itself is reversible and the blast radius is limited to the objects being written.

From the tool's definition Tool name is 'put_object_text' and description states 'Write a UTF-8 text object', which creates or modifies data in S3-compatible object storage.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

put_object_text Rate-limited

put_object_text 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": {
    "put_object_text": {
      "limits": [
        {
          "counter": "put_object_text_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 put_object_text

What does the put_object_text tool do? +

Write a UTF-8 text object. (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 put_object_text? +

Register the Rustfs MCP server in PolicyLayer and add a rule for put_object_text: 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 put_object_text? +

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

Can I rate-limit put_object_text? +

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

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

put_object_text 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.