wait_for · Selenium MCP: Risk & Policy

WHAT IT DOES

What wait_for does on Selenium

AI agents invoke wait_for to trigger actions in Selenium. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why wait_for needs a policy

wait_for performs a blocking operation that interacts with a live browser session and depends on page state. While not directly destructive or financial, it modifies the execution flow and browser state. Combined with sibling Execute tools (click, execute_js), misuse could enable automated attacks like credential harvesting, unauthorized form submissions, or malicious script injection.

From the tool's definition Tool is part of Selenium browser automation that 'waits until a CSS selector is visible' - a browser action that triggers external operations with side effects (page state changes, timing delays).

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

wait_for Rate-limited

wait_for 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.

View as policy code

policy.json

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

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Selenium, so you can run agents against it safely.

FAQ

Questions about wait_for

What does the wait_for tool do? +

Wait until a CSS selector is visible on the page. It is categorised as a Execute tool in the Selenium MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on wait_for? +

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

What risk level is wait_for? +

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

Can I rate-limit wait_for? +

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

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

wait_for is provided by the Selenium MCP server (scv-consultants/selenium-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.