AI agents invoke hover to trigger actions in Yandex Browser MCP Server. 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.
Hovering over an element is a browser action that can trigger UI side effects (dropdowns, tooltips, dynamic content loading). It doesn't read or write data persistently, but it executes an external operation in the browser. Severity is low since hover alone rarely causes significant harm, though it can be chained with other actions.
From the tool's definition 'Навести курсор на элемент' (Hover cursor over an element) — triggers browser interaction/action on a page element
Documented attack patterns abuse exactly the kind of access hover gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Yandex Browser MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for hover:
{
"version": "1",
"default": "deny",
"tools": {
"hover": {
"limits": [
{
"counter": "hover_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}hover 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.
Навести курсор на элемент. It is categorised as a Execute tool in the Yandex Browser MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Yandex Browser MCP Server MCP server in PolicyLayer and add a rule for hover: 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 Yandex Browser MCP Server. Nothing to install.
hover 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 hover 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 hover. 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.
hover is provided by the Yandex Browser MCP Server MCP server (t1trit/yandex-browser-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Yandex Browser MCP Server, 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.
18 Yandex Browser MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.