mcp_write · MCP CopyQ Server MCP: Risk & Policy

WHAT IT DOES

What mcp_write does on MCP CopyQ Server

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

WHY IT NEEDS A POLICY

Why mcp_write needs a policy

This tool creates or modifies clipboard data reversibly. Writing to clipboard is a side effect but not destructive (data can be overwritten or cleared) and not irreversible. The medium severity reflects that clipboard manipulation could leak sensitive data or interfere with user workflows, but lacks the blast radius of code execution or financial impact.

From the tool's definition Tool named 'mcp_write' on a server described as enabling 'writing...clipboard items.' The empty description limits certainty, but the name and server context clearly indicate write operations to clipboard data.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

mcp_write Rate-limited

mcp_write 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": {
    "mcp_write": {
      "limits": [
        {
          "counter": "mcp_write_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 MCP CopyQ Server, so you can run agents against it safely.

FAQ

Questions about mcp_write

What does the mcp_write tool do? +

mcp_write. It is categorised as a Write tool in the MCP CopyQ 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 mcp_write? +

Register the MCP CopyQ Server MCP server in PolicyLayer and add a rule for mcp_write: 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 CopyQ Server. Nothing to install.

What risk level is mcp_write? +

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

Can I rate-limit mcp_write? +

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

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

mcp_write is provided by the MCP CopyQ Server MCP server (list91/mcp-copyq). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.