High-risk tools in WebMCP
5 of the 13 tools in WebMCP are classified as high risk. This page profiles those tools specifically, with recommended policy actions and the attack patterns that target them.
Every operation listed below is an action PolicyLayer recommends controlling at the transport layer. Open any tool to see the full profile, risk score, and YAML policy snippet.
Tools at high risk
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call_extension_toolExecuteExecute a browser extension tool. Use this to call extension tools that provide browser-level functionality like tab management, bookmarks, history, etc.
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call_website_toolExecuteExecute a tool from a website MCP server. Use this to call website-specific tools that you discovered via list_website_tools.
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extension_tool_userscripts_test_executeExecuteTest execute a script without registering it (Chrome 135+)
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extension_tool_userscripts_configure_worldExecuteConfigure USER_SCRIPT world properties
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extension_tool_userscripts_registerExecuteRegister a new userscript with Chrome userScripts API
Attacks that target this class
High-risk tools in any server share these documented attack patterns. Each links to the full case and the defensive policy.