attach_task_file · ClickUp MCP: Risk & Policy

WHAT IT DOES

What attach_task_file does on ClickUp MCP

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

WHY IT NEEDS A POLICY

Why attach_task_file needs a policy

This tool creates or modifies data reversibly by attaching files to existing tasks. It does not delete, execute arbitrary code, or move funds. While it involves file handling across multiple sources (base64, URL, local paths), the core action is a write operation that adds metadata/attachments to a task.

From the tool's definition Attaches file to task with multiple file source options (base64, URL, local path, chunked uploads). This modifies task data by adding attachments, which is reversible (files can be detached).

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

attach_task_file Rate-limited

attach_task_file 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": {
    "attach_task_file": {
      "limits": [
        {
          "counter": "attach_task_file_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 ClickUp MCP, so you can run agents against it safely.

FAQ

Questions about attach_task_file

What does the attach_task_file tool do? +

Attaches file to task. Use taskId (preferred) or taskName + optional listName. File sources: 1) base64 + filename (≤10MB), 2) URL (http/https), 3) local path (absolute), 4) chunked for large files. WARNING: taskName without listName may match multiple tasks. It is categorised as a Write tool in the ClickUp MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on attach_task_file? +

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

What risk level is attach_task_file? +

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

Can I rate-limit attach_task_file? +

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

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

attach_task_file is provided by the ClickUp MCP server (twofeetup/clickup-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.