RECOMMENDED: Create hook script for function/fetch/xhr/property/cookie/websocket/eval/timer. Hooks run without pausing page execution and are the preferred approach over breakpoints for monitoring and interception.
AI agents invoke create_hook to trigger actions in JS Reverse Strong MCP. 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.
This tool injects and runs hook scripts into a live browser runtime environment, intercepting and potentially modifying function calls, network requests (fetch/XHR), cookies, WebSocket messages, eval, and timers. This constitutes code execution with broad access to sensitive browser-side data and behavior. Misuse could intercept credentials, session tokens, or manipulate application logic at runtime.
From the tool's definition Create hook script for function/fetch/xhr/property/cookie/websocket/eval/timer. Hooks run without pausing page execution and are the preferred approach over breakpoints for monitoring and interception.
Documented attack patterns abuse exactly the kind of access create_hook gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and JS Reverse Strong MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for create_hook:
{
"version": "1",
"default": "deny",
"tools": {
"create_hook": {
"limits": [
{
"counter": "create_hook_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}create_hook 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.
Free to start. No card required.
RECOMMENDED: Create hook script for function/fetch/xhr/property/cookie/websocket/eval/timer. Hooks run without pausing page execution and are the preferred approach over breakpoints for monitoring and interception. It is categorised as a Execute tool in the JS Reverse Strong MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the JS Reverse Strong MCP server in PolicyLayer and add a rule for create_hook: 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 JS Reverse Strong MCP. Nothing to install.
create_hook 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 create_hook 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 create_hook. 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.
create_hook is provided by the JS Reverse Strong MCP server (lwjjike/jsreverser-strong-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from JS Reverse Strong MCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
85 JS Reverse Strong MCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.