[LEGACY] Execute JavaScript in the browser context. Use interact_with_page instead.
AI agents invoke execute_browser_script to trigger actions in ZMCPTools. 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 executes arbitrary JavaScript in a browser environment, which can perform side effects including navigation, DOM manipulation, network requests, and information exfiltration. The legacy status and recommendation to use 'interact_with_page' instead does not diminish its risk profile.
From the tool's definition Tool name 'execute_browser_script' combined with description 'Execute JavaScript in the browser context' explicitly indicates arbitrary code execution capability.
Documented attack patterns abuse exactly the kind of access execute_browser_script gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and ZMCPTools, and nothing reaches the server without passing your rules. This is the rule we recommend for execute_browser_script:
{
"version": "1",
"default": "deny",
"tools": {
"execute_browser_script": {
"limits": [
{
"counter": "execute_browser_script_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}execute_browser_script 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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[LEGACY] Execute JavaScript in the browser context. Use interact_with_page instead. It is categorised as a Execute tool in the ZMCPTools MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the ZMCPTools MCP server in PolicyLayer and add a rule for execute_browser_script: 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 ZMCPTools. Nothing to install.
execute_browser_script 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_browser_script 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_browser_script. 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_browser_script is provided by the ZMCPTools MCP server (zachhandley/zmcptools). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 70 ZMCPTools tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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70 ZMCPTools tools catalogued and risk-classified — across an index of 42,500+ MCP servers.