AI agents call accessibility_tree to retrieve information from Kwin without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
An accessibility tree tool typically reads/queries the current state of UI elements without modifying anything. However, the empty description lowers confidence. Given the server context (desktop automation), this is likely a read operation that retrieves UI structure. Severity is medium because it could expose sensitive on-screen information.
From the tool's definition Tool name 'accessibility_tree' with empty description. By convention, accessibility tree tools retrieve the UI element hierarchy for inspection.
Documented attack patterns abuse exactly the kind of access accessibility_tree gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Kwin, and nothing reaches the server without passing your rules. This is the rule we recommend for accessibility_tree:
{
"version": "1",
"default": "deny",
"tools": {
"accessibility_tree": {}
}
}accessibility_tree is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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accessibility_tree. It is categorised as a Read tool in the Kwin MCP Server, which means it retrieves data without modifying state.
Register the Kwin MCP server in PolicyLayer and add a rule for accessibility_tree: 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 Kwin. Nothing to install.
accessibility_tree 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 accessibility_tree 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 accessibility_tree. 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.
accessibility_tree is provided by the Kwin MCP server (isac322/kwin-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Kwin, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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30 Kwin tools catalogued and risk-classified — across an index of 43,000+ MCP servers.