Run a Stagehand script (default export from defineScript) against the current browser session. Accepts either a file path or inline source — exactly one. Returns {status: "passed"|"failed", durationMs}. On failure also returns error and stack. Use after authoring a script to validate it; the MCP'...
Risk signalsAccepts file system path (path)
Part of the Browser Automation server.
Free to start. No card required.
AI agents invoke stagehand_run_script to trigger processes or run actions in Browser Automation. Execute operations can have side effects beyond the immediate call -- triggering builds, sending notifications, or starting workflows. Rate limits and argument validation are essential to prevent runaway execution.
stagehand_run_script can trigger processes with real-world consequences. An uncontrolled agent might start dozens of builds, send mass notifications, or kick off expensive compute jobs. PolicyLayer enforces rate limits and validates arguments to keep execution within safe bounds.
Execute tools trigger processes. Rate-limit and validate arguments to prevent unintended side effects.
{
"version": "1",
"default": "deny",
"tools": {
"stagehand_run_script": {
"limits": [
{
"counter": "stagehand_run_script_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}See the full Browser Automation policy for all 13 tools.
These attack patterns abuse exactly the kind of access stagehand_run_script gives an agent. Each links to the full case and the policy that stops it:
Other execute tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Run a Stagehand script (default export from defineScript) against the current browser session. Accepts either a file path or inline source — exactly one. Returns {status: "passed"|"failed", durationMs}. On failure also returns error and stack. Use after authoring a script to validate it; the MCP's live session is reused, so no separate setup is required. Inline source mode resolves bare imports against the MCP's own node_modules (no install needed); path mode resolves from the script's project.. It is categorised as a Execute tool in the Browser Automation MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Browser Automation MCP server in PolicyLayer and add a rule for stagehand_run_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 Browser Automation. Nothing to install.
stagehand_run_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 stagehand_run_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 stagehand_run_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.
stagehand_run_script is provided by the Browser Automation MCP server (@popoverai/browser-automation). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 13 Browser Automation tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
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