sheets_append_values · MCP Google Sheets Server MCP

WHAT IT DOES

What sheets_append_values does on MCP Google Sheets Server

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

WHY IT NEEDS A POLICY

Why sheets_append_values needs a policy

Appending values creates or modifies data in a spreadsheet but does not delete, destroy, or execute arbitrary code. The operation is reversible—appended values can be removed. This is clearly a Write category action. Severity is medium because unintended data additions could corrupt a spreadsheet's integrity, but the blast radius is limited to that single sheet and the operation can be undone.

From the tool's definition Tool description states 'Append values to the end of a table in a Google Sheets spreadsheet.' The term 'append' indicates adding new data to existing content, which is a reversible write operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

sheets_append_values Rate-limited

sheets_append_values 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_values": {
      "limits": [
        {
          "counter": "sheets_append_values_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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Instant setup, no code required.

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

FAQ

Questions about sheets_append_values

What does the sheets_append_values tool do? +

Append values to the end of a table in a Google Sheets spreadsheet. It is categorised as a Write tool in the MCP Google Sheets Server 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_values? +

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

What risk level is sheets_append_values? +

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

Can I rate-limit sheets_append_values? +

Yes. Add a rate_limit block to the sheets_append_values 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_values completely? +

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

sheets_append_values is provided by the MCP Google Sheets Server MCP server (oregpt/agenticledger_mcp_sheetsonly). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.