AI agents invoke list_insert_after to trigger actions in AWS Transform 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 performs a write/mutation operation on a list (inserting a value after a pivot element). This is a data modification operation. However, the description is vague and doesn't clarify whether this operates on a persistent data store or an in-memory structure. Given the ambiguity, Write is most applicable as it modifies existing data reversibly.
From the tool's definition 'Insert value after pivot in list' — modifies a list data structure by inserting a value
Documented attack patterns abuse exactly the kind of access list_insert_after gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and AWS Transform MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for list_insert_after:
{
"version": "1",
"default": "deny",
"tools": {
"list_insert_after": {
"limits": [
{
"counter": "list_insert_after_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}list_insert_after 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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Insert value after pivot in list. It is categorised as a Execute tool in the AWS Transform MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the AWS Transform MCP Server MCP server in PolicyLayer and add a rule for list_insert_after: 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 Transform MCP Server. Nothing to install.
list_insert_after 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_insert_after 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_insert_after. 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_insert_after is provided by the AWS Transform MCP Server MCP server (awslabs.aws-transform-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from AWS Transform MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
805 AWS Transform MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.