检查界面上是否存在包含指定文本的元素
AI agents call check_element_exists to retrieve information from Adb without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves information about UI elements and their properties without creating, modifying, deleting, or executing external operations. It is purely observational—similar to a search or query operation that returns boolean or state data. No side effects occur beyond reading the current UI state.
From the tool's definition Tool name 'check_element_exists' and description '检查界面上是否存在包含指定文本的元素' (check if an element containing specified text exists on the interface) indicates querying/checking UI state without modification or execution of commands.
Documented attack patterns abuse exactly the kind of access check_element_exists gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Adb, and nothing reaches the server without passing your rules. This is the rule we recommend for check_element_exists:
{
"version": "1",
"default": "deny",
"tools": {
"check_element_exists": {}
}
}check_element_exists is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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检查界面上是否存在包含指定文本的元素. It is categorised as a Read tool in the Adb MCP Server, which means it retrieves data without modifying state.
Register the Adb MCP server in PolicyLayer and add a rule for check_element_exists: 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 Adb. Nothing to install.
check_element_exists 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 check_element_exists 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 check_element_exists. 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.
check_element_exists is provided by the Adb MCP server (wolfcoming/adb_mcp_server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Adb, 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.
48 Adb tools catalogued and risk-classified — across an index of 43,000+ MCP servers.