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list_insert_after

Insert value after pivot in list.

How to control list_insert_after ↓

What list_insert_after does on AWS Step Functions Tool MCP Server

AI agents invoke list_insert_after 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.

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Why list_insert_after needs a policy

The tool description indicates it inserts a value into a list after a specified pivot element. This is a Write operation modifying data. However, the context is an AWS Step Functions MCP server, suggesting this may be a state machine list manipulation operation. The description is minimal and does not clarify whether this affects persistent AWS resources or in-memory state.

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:

How to control list_insert_after

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_insert_after:

policy.json
{
  "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.

  1. Create a free account and register AWS Step Functions Tool 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.
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Related tools and policies

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Questions about list_insert_after

What does the list_insert_after tool do? +

Insert value after pivot in 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.

How do I enforce a policy on list_insert_after? +

Register the AWS Step Functions Tool 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 Step Functions Tool MCP Server. Nothing to install.

What risk level is list_insert_after? +

list_insert_after is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit list_insert_after? +

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.

How do I block list_insert_after completely? +

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.

What MCP server provides list_insert_after? +

list_insert_after 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.

Enforce policy on every AWS Step Functions Tool MCP Server tool call.

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.

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