Medium Risk

list_trim

Trim list to specified range.

How to control list_trim ↓

What list_trim does on Amazon Location Service MCP Server

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

Medium Risk

Why list_trim needs a policy

Trimming a list to a specified range modifies the list by removing elements outside that range, which is a Write (or potentially Destructive) operation. However, the description is vague and the tool name 'list_trim' on an Amazon Location Service server is unusual.

From the tool's definition 'Trim list to specified range' - trimming implies modifying/reducing a list by removing elements outside a range

Documented attack patterns abuse exactly the kind of access list_trim gives an agent:

How to control list_trim

PolicyLayer is an MCP gateway — it sits between your AI agents and Amazon Location Service MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for list_trim:

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "list_trim": {
      "limits": [
        {
          "counter": "list_trim_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

list_trim 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.

  1. Create a free account and register Amazon Location Service MCP Server — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
LIMIT THIS TOOL →

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Related tools and policies

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Questions about list_trim

What does the list_trim tool do? +

Trim list to specified range. It is categorised as a Write tool in the Amazon Location Service 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 list_trim? +

Register the Amazon Location Service MCP Server MCP server in PolicyLayer and add a rule for list_trim: 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 Location Service MCP Server. Nothing to install.

What risk level is list_trim? +

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

Can I rate-limit list_trim? +

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

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

list_trim is provided by the Amazon Location Service MCP Server MCP server (awslabs.aws-location-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Amazon Location Service MCP Server tool call.

Start from Amazon Location Service MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

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805 Amazon Location Service MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.

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