append_to_array · Ast Editor MCP: Risk & Policy

WHAT IT DOES

What append_to_array does on Ast Editor

AI agents use append_to_array to create or update resources in Ast Editor — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Ast Editor environment.

WHY IT NEEDS A POLICY

Why append_to_array needs a policy

The tool appends data to arrays, which is a reversible modification (Write category). Severity is medium because it modifies code but changes are undoable and depend on the target array context rather than causing irreversible deletion or external effects. Confidence is 0.75 due to empty description; higher confidence would require explicit documentation of behavior and scope.

From the tool's definition Tool name 'append_to_array' and context from sibling tools (add_field, add_import, add_method, add_parameter, add_top_level) indicate this modifies code structure by adding elements to arrays. The description is empty, limiting certainty.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

append_to_array Rate-limited

append_to_array 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "append_to_array": {
      "limits": [
        {
          "counter": "append_to_array_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Ast Editor, so you can run agents against it safely.

FAQ

Questions about append_to_array

What does the append_to_array tool do? +

append_to_array. It is categorised as a Write tool in the Ast Editor MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on append_to_array? +

Register the Ast Editor MCP server in PolicyLayer and add a rule for append_to_array: 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 Ast Editor. Nothing to install.

What risk level is append_to_array? +

append_to_array is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit append_to_array? +

Yes. Add a rate_limit block to the append_to_array 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 append_to_array completely? +

Set action: deny in the PolicyLayer policy for append_to_array. 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 append_to_array? +

append_to_array is provided by the Ast Editor MCP server (kambleakash0/ast-editor). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.