List available classes in the ontology with instance counts. Args: - limit: Maximum number of classes to return (default: 50) - filter: Optional regex filter for class URI (case-insensitive) Returns: - List of classes with instance counts, ordered by count descending Examples: - No args: Returns ...
AI agents call explore_classes to retrieve information from Schema Gov It MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and queries metadata about ontology classes from the Italian government data catalog. It has no side effects—it only lists existing classes with instance counts and supports filtering/pagination. This is a pure read operation characteristic of data exploration and analysis tasks.
From the tool's definition Tool description states 'List available classes in the ontology with instance counts' and 'Returns: List of classes with instance counts, ordered by count descending'. The parameters (limit, filter) are for querying and filtering results.
Documented attack patterns abuse exactly the kind of access explore_classes gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Schema Gov It MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for explore_classes:
{
"version": "1",
"default": "deny",
"tools": {
"explore_classes": {}
}
}explore_classes is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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List available classes in the ontology with instance counts. Args: - limit: Maximum number of classes to return (default: 50) - filter: Optional regex filter for class URI (case-insensitive) Returns: - List of classes with instance counts, ordered by count descending Examples: - No args: Returns top 50 classes by instance count - filter=. It is categorised as a Read tool in the Schema Gov It MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Schema Gov It MCP Server MCP server in PolicyLayer and add a rule for explore_classes: 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 Schema Gov It MCP Server. Nothing to install.
explore_classes 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 explore_classes 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 explore_classes. 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.
explore_classes is provided by the Schema Gov It MCP Server MCP server (italia/dati-semantic-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Schema Gov It MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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47 Schema Gov It MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.