list_append_multiple
Append multiple values to list. Args: key: The name of the key values: List of values to append Returns: Success message or error message
This record as markdown: /tools/aws/list-append-multiple.md
What list_append_multiple does on AWS
AI agents use list_append_multiple 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.
Why list_append_multiple is rated Medium
The tool appends (adds) multiple values to an existing list structure, which is a reversible write/modification operation. It creates new data but does not delete or overwrite existing data. Severity is medium as it could modify data at scale by appending multiple values, but it is not irreversible.
From the tool's definition Append multiple values to list
Attacks that exploit this kind of access
The rule that runs list_append_multiple 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_append_multiple, this is the rule to start with:
list_append_multiple 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.
The button opens the PolicyLayer dashboard: create your workspace, connect AWS, apply this rule, and every list_append_multiple call is checked against it from then on.
Questions about list_append_multiple
Append multiple values to list. Args: key: The name of the key values: List of values to append Returns: Success message 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.
Register the AWS MCP server in PolicyLayer and add a rule for list_append_multiple: 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_append_multiple is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the list_append_multiple 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_append_multiple. 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_append_multiple 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.
More on AWS, and thousands of servers like it.
This server
Across the catalogue