List fields of a dataset with name, data type and description. Call before query_dataset to know which fields and filters are available.
Part of the Opendata Cat server.
Free to start. No card required.
AI agents call list_dataset_fields to retrieve information from Opendata Cat without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.
Even though list_dataset_fields only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.
Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.
{
"version": "1",
"default": "deny",
"tools": {
"list_dataset_fields": {}
}
}See the full Opendata Cat policy for all 8 tools.
These attack patterns abuse exactly the kind of access list_dataset_fields gives an agent. Each links to the full case and the policy that stops it:
Other read tools across the catalogue. The same approach applies to each: allow, with a rate cap to control cost.
List fields of a dataset with name, data type and description. Call before query_dataset to know which fields and filters are available.. It is categorised as a Read tool in the Opendata Cat MCP Server, which means it retrieves data without modifying state.
Register the Opendata Cat MCP server in PolicyLayer and add a rule for list_dataset_fields: 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 Opendata Cat. Nothing to install.
list_dataset_fields 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_dataset_fields 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_dataset_fields. 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_dataset_fields is provided by the Opendata Cat MCP server (@opendata.cat/mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 8 Opendata Cat tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
4,600+ MCP servers and 31,000+ tools scanned and risk-classified.