append_rows · Google Sheets OAuth MCP: Risk & Policy

WHAT IT DOES

What append_rows does on Google Sheets OAuth MCP

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

WHY IT NEEDS A POLICY

Why append_rows needs a policy

The tool creates new data (appends rows) in a spreadsheet owned by the user. While this modifies state, it is reversible and does not meet the threshold for Destructive (which requires irreversibility). The modification is limited to the user's own files via OAuth authentication, which constrains blast radius.

From the tool's definition Tool description states 'Append rows to the bottom of a Google Sheet', which modifies data by adding new rows. This is reversible: appended rows can be deleted afterward.

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 OAuth 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 OAuth 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 OAuth 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 OAuth 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 OAuth MCP server (rpieterse/mcp-studio-google-sheets-oauth-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.