cache_incr · AWS Labs MySQL MCP Server MCP: Risk & Policy

WHAT IT DOES

What cache_incr does on AWS Labs MySQL MCP Server

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

WHY IT NEEDS A POLICY

Why cache_incr needs a policy

The tool modifies an existing value in a cache by incrementing a counter. This is a reversible write operation (the counter can be decremented or reset), so it falls under Write rather than Execute or Destructive. Severity is medium because misuse could corrupt application state or rate-limiting logic relying on cache counters, but it does not delete data or run arbitrary code.

From the tool's definition Increment a counter in the cache

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

cache_incr Rate-limited

cache_incr 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_incr": {
      "limits": [
        {
          "counter": "cache_incr_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 Labs MySQL MCP Server, so you can run agents against it safely.

FAQ

Questions about cache_incr

What does the cache_incr tool do? +

Increment a counter in the cache. It is categorised as a Write tool in the AWS Labs MySQL 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_incr? +

Register the AWS Labs MySQL MCP Server MCP server in PolicyLayer and add a rule for cache_incr: 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 Labs MySQL MCP Server. Nothing to install.

What risk level is cache_incr? +

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

Can I rate-limit cache_incr? +

Yes. Add a rate_limit block to the cache_incr 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_incr completely? +

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

cache_incr is provided by the AWS Labs MySQL MCP Server MCP server (awslabs.mysql-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.