playwright_assert_element_count

THE RISK

High Risk

Why playwright_assert_element_count needs a policy

This tool executes a Playwright assertion in a browser session, which is an active operation that interacts with a running browser. While it is a read-like check, assertions in automation frameworks execute code and interact with external browser processes, placing it in the Execute category. Misuse could cause test failures or disrupt automation flows, but blast radius is moderate.

From the tool's definition 'Assert exact count of elements matching a selector with flexible comparison' — this triggers a browser assertion/check operation that executes a Playwright command against a live browser session

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

POLICY

How to control playwright_assert_element_count

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

policy.json

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

playwright_assert_element_count 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 RunAutomation 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

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All 91 RunAutomation MCP Server tools →

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Go deeper

High-risk tools in RunAutomation 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 playwright_assert_element_count

What does the playwright_assert_element_count tool do? +

Assert exact count of elements matching a selector with flexible comparison. It is categorised as a Execute tool in the RunAutomation 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 playwright_assert_element_count? +

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

What risk level is playwright_assert_element_count? +

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

Can I rate-limit playwright_assert_element_count? +

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

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

playwright_assert_element_count is provided by the RunAutomation MCP Server MCP server (tayyabakmal1/runautomation-mcpserver). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every RunAutomation MCP Server tool call.

Start from RunAutomation 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 →