AI agents invoke execute_js_safely to trigger actions in Js Reverse Analyzer. 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 runs JavaScript code dynamically with effects determined by the code arguments. Even with isolation claims, execution of untrusted or adversarial JavaScript poses significant risk: it can exfiltrate data, make HTTP requests, modify DOM, interact with external services, or perform other side effects depending on what code is executed.
From the tool's definition Tool name contains 'execute_js' and description states it executes JavaScript code in an isolated environment. Execution of arbitrary JavaScript code is inherently an Execute-category operation, regardless of claimed sandboxing.
Documented attack patterns abuse exactly the kind of access execute_js_safely gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Js Reverse Analyzer, and nothing reaches the server without passing your rules. This is the rule we recommend for execute_js_safely:
{
"version": "1",
"default": "deny",
"tools": {
"execute_js_safely": {
"limits": [
{
"counter": "execute_js_safely_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}execute_js_safely 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.
在隔离环境中安全执行 JavaScript 代码. It is categorised as a Execute tool in the Js Reverse Analyzer MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Js Reverse Analyzer MCP server in PolicyLayer and add a rule for execute_js_safely: 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 Analyzer. Nothing to install.
execute_js_safely 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 execute_js_safely 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 execute_js_safely. 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.
execute_js_safely is provided by the Js Reverse Analyzer MCP server (sjhhh024-cmyk/spider-js-mcp-skills). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Js Reverse Analyzer, 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.
13 Js Reverse Analyzer tools catalogued and risk-classified — across an index of 43,000+ MCP servers.