Prepend multiple values to list.
AI agents invoke list_prepend_multiple to trigger actions in AWS Step Functions Tool MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
The tool modifies a list by prepending multiple values. This is a Write-level operation at minimum. However, the context is an AWS Step Functions MCP server, suggesting this may be a Step Functions state/data manipulation operation. The description is minimal and uninformative about whether this affects persisted state or is part of a workflow execution.
From the tool's definition Tool name: 'list_prepend_multiple', description: 'Prepend multiple values to list.'
Documented attack patterns abuse exactly the kind of access list_prepend_multiple gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and AWS Step Functions Tool MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for list_prepend_multiple:
{
"version": "1",
"default": "deny",
"tools": {
"list_prepend_multiple": {
"limits": [
{
"counter": "list_prepend_multiple_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
} list_prepend_multiple stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
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Prepend multiple values to list. It is categorised as a Execute tool in the AWS Step Functions Tool MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the AWS Step Functions Tool MCP Server MCP server in PolicyLayer and add a rule for list_prepend_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 Step Functions Tool MCP Server. Nothing to install.
list_prepend_multiple is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the list_prepend_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_prepend_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_prepend_multiple is provided by the AWS Step Functions Tool MCP Server MCP server (awslabs.stepfunctions-tool-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from AWS Step Functions Tool 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 AWS Step Functions Tool MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.