AI agents invoke run_js to trigger actions in DrissionPageMCP. 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.
JavaScript execution in a browser controlled by an AI agent represents critical risk. An agent could run arbitrary JS to steal data, modify page content, exfiltrate credentials, perform unauthorized actions, or pivot to backend systems. This is Execute (code execution) with critical severity due to the broad attack surface and lack of input constraints evident from the empty description.
From the tool's definition Tool name 'run_js' in a browser automation context (DrissionPage MCP server) with sibling tools like 'element_click', 'element_input', and 'connect_or_open_browser'. The server description explicitly mentions 'JavaScript execution' as a capability.
Documented attack patterns abuse exactly the kind of access run_js gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and DrissionPageMCP, and nothing reaches the server without passing your rules. This is the rule we recommend for run_js:
{
"version": "1",
"default": "deny",
"tools": {
"run_js": {
"limits": [
{
"counter": "run_js_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}run_js 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.
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run_js. It is categorised as a Execute tool in the DrissionPageMCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the DrissionPage MCP server in PolicyLayer and add a rule for run_js: 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 DrissionPageMCP. Nothing to install.
run_js is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the run_js 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.
Set action: deny in the PolicyLayer policy for run_js. 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.
run_js is provided by the DrissionPage MCP server (wxhzhwxhzh/drissionpagemcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 37 DrissionPageMCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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37 DrissionPageMCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.