Capture a screenshot of the current page. Returns base64 PNG. Most action tools (navigate, click, type) already return screenshots — use this only when you need an extra screenshot without performing an action.
AI agents call browser_screenshot to retrieve information from Yaver without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
session_id | string | Yes | Session ID |
Parameters from the server's own tool schema.
Even though browser_screenshot only reads data, uncontrolled read access leaks sensitive information and racks up API costs — an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.
Attacks that exploit this kind of access
Capture a screenshot of the current page. Returns base64 PNG. Most action tools (navigate, click, type) already return screenshots — use this only when you need an extra screenshot without performing an action. It is categorised as a Read tool in the Yaver MCP Server, which means it retrieves data without modifying state.
browser_screenshot accepts 1 parameter: session_id. Required: session_id. The full parameter table on this page comes from the server's own tool schema.
Register the Yaver MCP server in PolicyLayer and add a rule for browser_screenshot: 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 Yaver. Nothing to install.
browser_screenshot is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the browser_screenshot 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 browser_screenshot. 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.
browser_screenshot is provided by the Yaver MCP server (yaver-cli). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.