Set the viewport size of the page
AI agents invoke puppeteer_set_viewport to trigger actions in Claude TypeScript MCP Servers. 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 controls a browser (Puppeteer) by setting the viewport dimensions. It triggers an external browser operation that changes the rendering state of a page. While not destructive or financial, it executes a browser action that affects subsequent page behavior and screenshots, placing it in the Execute category.
From the tool's definition Set the viewport size of the page
Documented attack patterns abuse exactly the kind of access puppeteer_set_viewport gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Claude TypeScript MCP Servers, and nothing reaches the server without passing your rules. This is the rule we recommend for puppeteer_set_viewport:
{
"version": "1",
"default": "deny",
"tools": {
"puppeteer_set_viewport": {
"limits": [
{
"counter": "puppeteer_set_viewport_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
} puppeteer_set_viewport 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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Set the viewport size of the page. It is categorised as a Execute tool in the Claude TypeScript MCP Servers MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Claude TypeScript MCP Servers MCP server in PolicyLayer and add a rule for puppeteer_set_viewport: 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 Claude TypeScript MCP Servers. Nothing to install.
puppeteer_set_viewport 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 puppeteer_set_viewport 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 puppeteer_set_viewport. 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.
puppeteer_set_viewport is provided by the Claude TypeScript MCP Servers MCP server (ukkz/claude-ts-mcps). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Claude TypeScript MCP Servers, 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.
84 Claude TypeScript MCP Servers tools catalogued and risk-classified — across an index of 43,000+ MCP servers.