Obscure MCP API in Comet Browser Breaches User Trust, Enabling Full Device Control via AI Browsers
SquareX released critical research exposing a hidden API in Comet that allows extensions in the AI Browser to execute local commands and gain full control over users' devices. The research reveals that Comet has implemented a MCP API (chrome.perplexity.mcp.addStdioServer) that allows its embedded extensions to execute arbitrary local commands on users' devices, capabilities that traditional browsers explicitly prohibit. Concerningly, there is limited official documentation on the MCP API.