append_rows · Google Sheets MCP: Risk & Policy

WHAT IT DOES

What append_rows does on Google Sheets MCP

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

WHY IT NEEDS A POLICY

Why append_rows needs a policy

This tool creates new data in a spreadsheet without permanently destroying existing data or executing arbitrary code. It is reversible (appended rows can be deleted), distinguishing it from Destructive. It does not read-only (hence not Read), execute code (hence not Execute), or involve financial transactions (hence not Financial). Write is the most accurate category.

From the tool's definition Tool name 'append_rows' and description 'Append rows to the bottom of a Google Sheet' indicate creation of new data that is reversible (rows can be deleted).

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

append_rows Rate-limited

append_rows 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_rows": {
      "limits": [
        {
          "counter": "append_rows_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 Google Sheets MCP, so you can run agents against it safely.

FAQ

Questions about append_rows

What does the append_rows tool do? +

Append rows to the bottom of a Google Sheet. Each row is an array of cell values. It is categorised as a Write tool in the Google Sheets MCP 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_rows? +

Register the Google Sheets MCP server in PolicyLayer and add a rule for append_rows: 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 Google Sheets MCP. Nothing to install.

What risk level is append_rows? +

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

Can I rate-limit append_rows? +

Yes. Add a rate_limit block to the append_rows 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_rows completely? +

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

append_rows is provided by the Google Sheets MCP server (rpieterse/mcp-studio-google-sheets-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.