write_cell · Wps MCP: Risk & Policy

WHAT IT DOES

What write_cell does on Wps

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

WHY IT NEEDS A POLICY

Why write_cell needs a policy

This tool creates or modifies data within spreadsheet cells in a reversible manner. It does not execute arbitrary code, delete data irreversibly, or move money. The blast radius is medium because modifying spreadsheet values could corrupt calculations, reports, or business data if misused by an agent, but the changes are reversible through undo or manual correction.

From the tool's definition Tool name 'write_cell' and description 'Write a value to a cell' indicate the tool modifies cell data in a spreadsheet.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

write_cell Rate-limited

write_cell 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_cell": {
      "limits": [
        {
          "counter": "write_cell_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 Wps, so you can run agents against it safely.

FAQ

Questions about write_cell

What does the write_cell tool do? +

Write a value to a cell. It is categorised as a Write tool in the Wps 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_cell? +

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

What risk level is write_cell? +

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

Can I rate-limit write_cell? +

Yes. Add a rate_limit block to the write_cell 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_cell completely? +

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

write_cell is provided by the Wps MCP server (xiao-rx/wps-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.