attach_file · Mcp Zotero MCP: Risk & Policy

WHAT IT DOES

What attach_file does on Mcp Zotero

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

WHY IT NEEDS A POLICY

Why attach_file needs a policy

This tool modifies existing data by adding an attachment relationship to an item, which is a reversible write operation. It does not delete data (ruling out Destructive), execute arbitrary code (ruling out Execute), or move money (ruling out Financial). The severity is medium because attachment operations could introduce large files or unintended links, but the blast radius is contained to a single item's metadata.

From the tool's definition 'Attach a local file to an existing item' — creates a new attachment association with a Zotero item, modifying the item's metadata and attachment list.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

attach_file Rate-limited

attach_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_file": {
      "limits": [
        {
          "counter": "attach_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 Mcp Zotero, so you can run agents against it safely.

FAQ

Questions about attach_file

What does the attach_file tool do? +

Attach a local file to an existing item (best-effort). It is categorised as a Write tool in the Mcp Zotero 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_file? +

Register the Mcp Zotero MCP server in PolicyLayer and add a rule for attach_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 Mcp Zotero. Nothing to install.

What risk level is attach_file? +

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

Can I rate-limit attach_file? +

Yes. Add a rate_limit block to the attach_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_file completely? +

Set action: deny in the PolicyLayer policy for attach_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_file? +

attach_file is provided by the Mcp Zotero MCP server (nealcaren/mcp-zotero). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.