hook_function
Hooks a JavaScript function to log its calls, arguments, and return values. Useful for understanding how functions are used without setting breakpoints.
This record as markdown: /tools/1600822305-js-reverse-mcp/hook-function.md
What hook_function does on Js Reverse
AI agents invoke hook_function to trigger actions in Js Reverse. 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 hook_function is rated High
Hooking a function requires executing code injection into the browser's JavaScript runtime. This is an active execution operation that modifies the runtime behavior of the target page. While described as non-intrusive (no breakpoints), it still runs injected code in the browser context, which could be misused to intercept sensitive data (credentials, tokens, PII) passed through hooked functions.
From the tool's definition 'Hooks a JavaScript function' — injects instrumentation code into a running browser context to intercept function calls, arguments, and return values
Attacks that exploit this kind of access
The rule that runs hook_function safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Js Reverse, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For hook_function, this is the rule to start with:
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.
The button opens the PolicyLayer dashboard: create your workspace, connect Js Reverse, apply this rule, and every hook_function call is checked against it from then on.
Questions about hook_function
Hooks a JavaScript function to log its calls, arguments, and return values. Useful for understanding how functions are used without setting breakpoints. It is categorised as a Execute tool in the Js Reverse MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Js Reverse 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. 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 MCP server (1600822305/js-reverse-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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