AI agents call discover_workspace_data to retrieve information from Fabric Ontology MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Despite the empty description, the naming pattern (discover_*) and placement among CRUD tools in a metadata/ontology server indicates this tool queries or lists workspace data without modifying it. The verb 'discover' implies enumeration or retrieval. Confidence is reduced slightly due to the empty description, but the pattern and context strongly suggest a Read operation with low blast radius.
From the tool's definition Tool name 'discover_workspace_data' combined with server context indicating 'workspace discovery through natural language' and sibling tools like 'discover_lakehouse_tables' suggests a retrieval/query operation.
Documented attack patterns abuse exactly the kind of access discover_workspace_data gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Fabric Ontology MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for discover_workspace_data:
{
"version": "1",
"default": "deny",
"tools": {
"discover_workspace_data": {}
}
} discover_workspace_data is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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discover_workspace_data. It is categorised as a Read tool in the Fabric Ontology MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Fabric Ontology MCP Server MCP server in PolicyLayer and add a rule for discover_workspace_data: 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 Fabric Ontology MCP Server. Nothing to install.
discover_workspace_data 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 discover_workspace_data 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 discover_workspace_data. 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.
discover_workspace_data is provided by the Fabric Ontology MCP Server MCP server (tmdaidevs/ontology-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Fabric Ontology 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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45 Fabric Ontology MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.