string_decrement · Amazon MQ MCP Server MCP: Risk & Policy

WHAT IT DOES

What string_decrement does on Amazon MQ MCP Server

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

WHY IT NEEDS A POLICY

Why string_decrement needs a policy

The tool decrements an integer value, which is a modification operation (Write). However, the description is minimal and uninformative about what exactly is being decremented (a counter, a configuration value, etc.), which lowers confidence. In the context of an Amazon MQ broker management server, this could affect broker configuration or resource counts.

From the tool's definition 'Decrement integer value' - modifies a numeric value

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

string_decrement Rate-limited

string_decrement 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": {
    "string_decrement": {
      "limits": [
        {
          "counter": "string_decrement_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 Amazon MQ MCP Server, so you can run agents against it safely.

FAQ

Questions about string_decrement

What does the string_decrement tool do? +

Decrement integer value. It is categorised as a Write tool in the Amazon MQ MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on string_decrement? +

Register the Amazon MQ MCP Server MCP server in PolicyLayer and add a rule for string_decrement: 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 Amazon MQ MCP Server. Nothing to install.

What risk level is string_decrement? +

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

Can I rate-limit string_decrement? +

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

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

string_decrement is provided by the Amazon MQ MCP Server MCP server (awslabs.amazon-mq-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.