Fetch the available thematic categories from the Open Knowledge Graphs (OKG) catalog. Returns: List of category names that can be used as filters in search_okg_resources and compare_coverage_with_okg. Use when: You need to know which categories are available before filtering OKG searches.
AI agents call list_okg_categories 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 only retrieves and queries metadata (available thematic categories) with no side effects, creation of new data, code execution, or data modification. It is a pure read operation on a catalog's informational content. The low severity reflects minimal blast radius—misuse would only affect information retrieval, not system state or data integrity.
From the tool's definition Tool performs a 'Fetch' operation to retrieve a list of category names from the OKG catalog. The description explicitly states it returns data without modification and is used to inform subsequent filtering decisions ('can be used as filters').
Documented attack patterns abuse exactly the kind of access list_okg_categories 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 list_okg_categories:
{
"version": "1",
"default": "deny",
"tools": {
"list_okg_categories": {}
}
}list_okg_categories is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Fetch the available thematic categories from the Open Knowledge Graphs (OKG) catalog. Returns: List of category names that can be used as filters in search_okg_resources and compare_coverage_with_okg. Use when: You need to know which categories are available before filtering OKG searches. 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 list_okg_categories: 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.
list_okg_categories 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 list_okg_categories 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 list_okg_categories. 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.
list_okg_categories 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.
Free to start. No card required.
47 Schema Gov It MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.