write_sheet · Datahub MCP: Risk & Policy

WHAT IT DOES

What write_sheet does on DatahubMCP

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

WHY IT NEEDS A POLICY

Why write_sheet needs a policy

An AI agent can call write_sheet faster than any human can review — one bad instruction and it creates or modifies resources in DatahubMCP by the hundred, each call as confident as the last.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

write_sheet Rate-limited

write_sheet 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": {
    "write_sheet": {
      "limits": [
        {
          "counter": "write_sheet_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 DatahubMCP, so you can run agents against it safely.

FAQ

Questions about write_sheet

What does the write_sheet tool do? +

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

How do I enforce a policy on write_sheet? +

Register the Datahub MCP server in PolicyLayer and add a rule for write_sheet: 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 DatahubMCP. Nothing to install.

What risk level is write_sheet? +

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

Can I rate-limit write_sheet? +

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

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

write_sheet is provided by the Datahub MCP server (yucheuan/datahubmcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.