spreadsheet_write_styles

THE RISK

Medium Risk

Why spreadsheet_write_styles needs a policy

This tool creates or modifies spreadsheet formatting in a reversible manner. While it affects the appearance of cells, it does not delete data, execute code, trigger external operations, or move money. The changes can be undone (typical undo functionality in spreadsheet applications).

From the tool's definition Tool description states 'Bulk overwrite cell styles' — modifies formatting attributes (fonts, colors, alignment, number formats, borders) within a spreadsheet, which is a reversible change to data presentation layer.

Documented attack patterns abuse exactly the kind of access spreadsheet_write_styles gives an agent:

POLICY

How to control spreadsheet_write_styles

PolicyLayer is an MCP gateway — it sits between your AI agents and Synology Office, and nothing reaches the server without passing your rules. This is the rule we recommend for spreadsheet_write_styles:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "spreadsheet_write_styles": {
      "limits": [
        {
          "counter": "spreadsheet_write_styles_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

spreadsheet_write_styles 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.

Create a free account and register Synology Office — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Synology Office tools

Destructive calendar_delete_event Delete a Synology Calendar event permanently. Requires confirm=true. Destructive drive_delete_file Delete a file or folder in Synology Drive (moves to trash by default). Set confirm=true to Destructive spreadsheet_delete_file WARNING: Permanently delete an ENTIRE spreadsheet file (.osheet). Destructive spreadsheet_delete_sheet Delete a sheet tab from a Synology Spreadsheet. This action cannot be undone. Provide eith Write spreadsheet_append_rows Append rows to the end of existing data in a Synology Spreadsheet sheet. Provide either fi Write drive_get_sharing_link Generate or retrieve a sharing link for a Synology Drive file with configurable permission Write calendar_create_calendar Create a new Synology Calendar. Write calendar_create_event Create a new Synology Calendar event. Requires confirm=true.

All 39 Synology Office tools →

Write tools on other servers

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about spreadsheet_write_styles

What does the spreadsheet_write_styles tool do? +

Bulk overwrite cell styles (fonts, colors, alignment, number formats, borders) for a rectangular block in a Synology Spreadsheet. It is categorised as a Write tool in the Synology Office MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on spreadsheet_write_styles? +

Register the Synology Office MCP server in PolicyLayer and add a rule for spreadsheet_write_styles: 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 Synology Office. Nothing to install.

What risk level is spreadsheet_write_styles? +

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

Can I rate-limit spreadsheet_write_styles? +

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

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

spreadsheet_write_styles is provided by the Synology Office MCP server (vocweb/synology-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Synology Office tool call.

Start from Synology Office, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →