AI agents call create-react-ui to retrieve information from Ava without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool appears to return a React UI component, which is a read/generation operation with no described side effects. It does not write, delete, execute commands, or make financial transactions. The description is minimal, which lowers confidence slightly, but there is no indication of destructive or write behavior. Severity is low as misuse would at most return an unintended UI definition.
From the tool's definition 'Returns a React-based UI' — the description indicates the tool returns/generates a UI component
Documented attack patterns abuse exactly the kind of access create-react-ui gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Ava, and nothing reaches the server without passing your rules. This is the rule we recommend for create-react-ui:
{
"version": "1",
"default": "deny",
"tools": {
"create-react-ui": {}
}
}create-react-ui is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Returns a React-based UI. It is categorised as a Read tool in the Ava MCP Server, which means it retrieves data without modifying state.
Register the Ava MCP server in PolicyLayer and add a rule for create-react-ui: 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 Ava. Nothing to install.
create-react-ui 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 create-react-ui 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 create-react-ui. 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.
create-react-ui is provided by the Ava MCP server (yutakobayashidev/ava). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Ava, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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10 Ava tools catalogued and risk-classified — across an index of 43,000+ MCP servers.