cache_decr

Decrement a counter in the cache. Args: key: The key to decrement value: Amount to decrement by (default 1) Returns: New value or error message

SERVERAWS SOURCE@awslabs/mcp

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity verified Pull the record →

This record as markdown: /tools/aws/cache-decr.md

WHAT IT DOES

What cache_decr does on AWS

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

RISK

Why cache_decr is rated Medium

This tool modifies an existing value in the cache by decrementing a counter. It is a write operation (mutates state) but is generally reversible (the counter can be incremented back). Misuse could corrupt application state or logic that depends on cache counters, hence medium severity.

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

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs cache_decr safely

PolicyLayer is an MCP gateway: it sits between your AI agents and AWS, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For cache_decr, this is the rule to start with:

cache_decr Rate-limited

cache_decr 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_decr": {
      "limits": [
        {
          "counter": "cache_decr_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect AWS, apply this rule, and every cache_decr call is checked against it from then on.

FAQ

Questions about cache_decr

What does the cache_decr tool do? +

Decrement a counter in the cache. Args: key: The key to decrement value: Amount to decrement by (default 1) Returns: New value or error message. It is categorised as a Write tool in the AWS 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_decr? +

Register the AWS MCP server in PolicyLayer and add a rule for cache_decr: 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. Nothing to install.

What risk level is cache_decr? +

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

Can I rate-limit cache_decr? +

Yes. Add a rate_limit block to the cache_decr 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_decr completely? +

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

cache_decr is provided by the AWS MCP server (@awslabs/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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