sheets_append · Access MCP: Risk & Policy

WHAT IT DOES

What sheets_append does on Access

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

WHY IT NEEDS A POLICY

Why sheets_append needs a policy

The tool creates new rows in a spreadsheet, which is a reversible write operation (rows can be deleted). It modifies data but does not irreversibly destroy existing data, placing it in the Write category. Severity is medium because an AI agent could append large volumes of unwanted or sensitive data to shared spreadsheets.

From the tool's definition Append one or more rows to the bottom of a Google Sheets spreadsheet... Side effect: modifies the spreadsheet immediately.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

sheets_append Rate-limited

sheets_append 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": {
    "sheets_append": {
      "limits": [
        {
          "counter": "sheets_append_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 Access, so you can run agents against it safely.

FAQ

Questions about sheets_append

What does the sheets_append tool do? +

Append one or more rows to the bottom of a Google Sheets spreadsheet. New rows are added after the last row with data. Side effect: modifies the spreadsheet immediately. It is categorised as a Write tool in the Access MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on sheets_append? +

Register the Access MCP server in PolicyLayer and add a rule for sheets_append: 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 Access. Nothing to install.

What risk level is sheets_append? +

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

Can I rate-limit sheets_append? +

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

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

sheets_append is provided by the Access MCP server (scottpedia0/access). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.