This record as markdown: /tools/aws/list-trim.md
What list_trim does on AWS
AI agents call list_trim to permanently remove resources in AWS, typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Why list_trim is rated Critical
LTRIM (Redis list trim) removes all elements outside the specified start/stop range. This is an irreversible deletion of data; elements outside the range are discarded and cannot be recovered without a backup. This qualifies as Destructive rather than Write because the removal of data is not easily reversible.
From the tool's definition "Trim list to specified range" — elements outside the specified range are permanently removed from the list
Attacks that exploit this kind of access
The rule that runs list_trim 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 list_trim, this is the rule to start with:
list_trim is removed from the agent's tool list entirely, so the agent never calls it. The rest of the server keeps working.
The button opens the PolicyLayer dashboard: create your workspace, connect AWS, apply this rule, and every list_trim call is checked against it from then on.
Questions about list_trim
Trim list to specified range. Args: key: The name of the key start: Start index (inclusive) stop: Stop index (inclusive) Returns: Success message or error message. It is categorised as a Destructive tool in the AWS MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the AWS 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 AWS. Nothing to install.
list_trim is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
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.
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.
list_trim 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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