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

WHAT IT DOES

What cache_touch does on AWS IoT SiteWise MCP Server

AI agents use cache_touch 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 cache_touch needs a policy

The tool modifies cache key properties (specifically expiration time) but does not create, delete, or destroy data. This is a Write operation because it changes state reversibly. Severity is low because cache expiration updates have minimal blast radius—they affect only cache behavior and can be easily reverted or reset.

From the tool's definition Tool name 'cache_touch' and description 'Update the expiration time for a key' indicates modification of cache metadata (TTL/expiration), which is a reversible write operation on existing data.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

cache_touch Rate-limited

cache_touch 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": {
    "cache_touch": {
      "limits": [
        {
          "counter": "cache_touch_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 cache_touch

What does the cache_touch tool do? +

Update the expiration time for a key. 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 cache_touch? +

Register the AWS IoT SiteWise MCP Server MCP server in PolicyLayer and add a rule for cache_touch: 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 cache_touch? +

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

Can I rate-limit cache_touch? +

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

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

cache_touch 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.