List all available data categories
AI agents call list_categories to retrieve information from Opera Omnia MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a read-only operation that enumerates available categories in the Opera Omnia dataset collection. It has no side effects, does not execute code, does not modify data, and does not involve financial transactions. The blast radius of misuse is minimal—an agent can only learn what categories exist, which is non-sensitive metadata discovery.
From the tool's definition Tool name 'list_categories' and description 'List all available data categories' indicate a query operation that retrieves metadata without modifying, executing, or deleting data.
Attacks that exploit this kind of access
List all available data categories. It is categorised as a Read tool in the Opera Omnia MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Opera Omnia MCP Server MCP server in PolicyLayer and add a rule for list_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 Opera Omnia MCP Server. Nothing to install.
list_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_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_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_categories is provided by the Opera Omnia MCP Server MCP server (triptych/opera-omnia-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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