RECOMMENDED for reverse engineering: Hooks a JavaScript function to log its calls, arguments, and return values without pausing execution. More reliable than breakpoints for automated workflows. Use this as the default approach for monitoring functions.
AI agents invoke hook_function 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.
Hooking a function requires executing code injection into a live JavaScript environment. While the stated purpose is observational (logging), the mechanism is code execution/instrumentation that modifies runtime behavior.
From the tool's definition 'Hooks a JavaScript function to log its calls, arguments, and return values without pausing execution' — injects hook code into a running JavaScript runtime to intercept function calls
Documented attack patterns abuse exactly the kind of access hook_function 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 hook_function:
{
"version": "1",
"default": "deny",
"tools": {
"hook_function": {
"limits": [
{
"counter": "hook_function_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}hook_function 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 for reverse engineering: Hooks a JavaScript function to log its calls, arguments, and return values without pausing execution. More reliable than breakpoints for automated workflows. Use this as the default approach for monitoring functions. 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 hook_function: 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.
hook_function 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 hook_function 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 hook_function. 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.
hook_function 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.