set_add · AWS IoT SiteWise MCP Server MCP: Risk & Policy

WHAT IT DOES

What set_add does on AWS IoT SiteWise MCP Server

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

WHY IT NEEDS A POLICY

Why set_add needs a policy

This tool creates or modifies membership relationships by adding a member to a set. While reversible (the member could be removed later), it alters state and access control configurations. It does not delete data or execute arbitrary code, so it falls under Write rather than Destructive or Execute.

From the tool's definition Tool name 'set_add' and description 'Add member to set' indicate a create/modify operation that adds data to a collection. In AWS IoT SiteWise context, this modifies group or set membership, which is reversible via removal.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_add Rate-limited

set_add 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": {
    "set_add": {
      "limits": [
        {
          "counter": "set_add_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 AWS IoT SiteWise MCP Server, so you can run agents against it safely.

FAQ

Questions about set_add

What does the set_add tool do? +

Add member to set. It is categorised as a Write tool in the AWS IoT SiteWise 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 set_add? +

Register the AWS IoT SiteWise MCP Server MCP server in PolicyLayer and add a rule for set_add: 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 AWS IoT SiteWise MCP Server. Nothing to install.

What risk level is set_add? +

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

Can I rate-limit set_add? +

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

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

set_add is provided by the AWS IoT SiteWise MCP Server MCP server (awslabs.aws-iot-sitewise-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.