vercel-blob-put-file · Mcp Gmail MCP: Risk & Policy

WHAT IT DOES

What vercel-blob-put-file does on Mcp Gmail

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

WHY IT NEEDS A POLICY

Why vercel-blob-put-file needs a policy

This tool performs a file upload to external cloud storage (Vercel Blob), which is a Write operation that creates or modifies data. While reversible (files can be overwritten or deleted separately), the upload itself creates new data artifacts.

From the tool's definition Tool description states 'Upload a file to Vercel Blob storage' and 'file will be read, converted to base64, and uploaded automatically.' The upload operation creates or modifies data in cloud storage.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

vercel-blob-put-file Rate-limited

vercel-blob-put-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": {
    "vercel-blob-put-file": {
      "limits": [
        {
          "counter": "vercel-blob-put-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 Gmail, so you can run agents against it safely.

FAQ

Questions about vercel-blob-put-file

What does the vercel-blob-put-file tool do? +

Upload a file to Vercel Blob storage by providing the full file path. The file will be read, converted to base64, and uploaded automatically. It is categorised as a Write tool in the Mcp Gmail MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on vercel-blob-put-file? +

Register the Mcp Gmail MCP server in PolicyLayer and add a rule for vercel-blob-put-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 Gmail. Nothing to install.

What risk level is vercel-blob-put-file? +

vercel-blob-put-file is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit vercel-blob-put-file? +

Yes. Add a rate_limit block to the vercel-blob-put-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 vercel-blob-put-file completely? +

Set action: deny in the PolicyLayer policy for vercel-blob-put-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 vercel-blob-put-file? +

vercel-blob-put-file is provided by the Mcp Gmail MCP server (@monsoft/mcp-gmail). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.