element_wait

THE RISK

High Risk

Why element_wait needs a policy

While 'element_wait' itself is passive (waiting rather than directly modifying), it is part of a browser automation suite (Playwright via Firefox) that allows executing arbitrary browser actions. The tool's purpose is to synchronize automation workflows with page state changes—a prerequisite for executing subsequent actions (e.g., waiting for a form field before filling it, waiting for a button before clicking).

From the tool's definition Tool enables waiting for elements to appear or become visible through Playwright browser automation. The description explicitly references 'handling dynamic content and loading states,' indicating it can pause execution pending specific conditions.

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

POLICY

How to control element_wait

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

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "element_wait": {
      "limits": [
        {
          "counter": "element_wait_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

element_wait stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

Create a free account and register Firefox MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RATE-LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Firefox MCP Server tools

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All 29 Firefox MCP Server tools →

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Go deeper

High-risk tools in Firefox MCP Server → Every high-risk tool this server exposes, in one view.
All high-risk MCP tools → Every high-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Agent sandbox → Bounding what an agent can execute and where the boundary should sit.
Least privilege for MCP → Granting agents the minimum tool surface the task needs.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about element_wait

What does the element_wait tool do? +

Wait for specific elements to appear or become visible. Essential for handling dynamic content and loading states. It is categorised as a Execute tool in the Firefox MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on element_wait? +

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

What risk level is element_wait? +

element_wait is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit element_wait? +

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

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

element_wait is provided by the Firefox MCP Server MCP server (jediluke/firefox-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 Firefox MCP Server tool call.

Start from Firefox MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →