Medium Risk

add_domain

Add a domain to a project

How to control add_domain ↓

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

Medium Risk

Adding a domain modifies project settings by creating a new domain-to-project binding. This is a write operation (reversible via domain removal) rather than read-only or destructive. The blast radius is medium because misconfiguration could redirect traffic or cause service disruption, but the action itself is not irreversible like deletion and does not involve financial transactions or arbitrary code execution.

From the tool's definition Tool name is 'add_domain' and description states 'Add a domain to a project' — this creates a new domain association, which is a reversible modification to project configuration.

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

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

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "add_domain": {
      "limits": [
        {
          "counter": "add_domain_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

add_domain 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.

  1. Create a free account and register Vercel MCP Server — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
LIMIT THIS TOOL →

Free to start. No card required.

Go deeper

What does the add_domain tool do? +

Add a domain to a project. It is categorised as a Write tool in the Vercel MCP 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 add_domain? +

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

What risk level is add_domain? +

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

Can I rate-limit add_domain? +

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

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

add_domain is provided by the Vercel MCP Server MCP server (quegenx/vercel-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 Vercel MCP Server tool call.

Deterministic rules across all 154 Vercel MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.

Free to start. No card required.

154 Vercel MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.

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