Get the schema of an external table
AI agents call retrieve_external_table_schema to retrieve information from Kusto 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 schema information about external tables in Azure Data Explorer. Schema queries are informational reads with no side effects. The word "retrieve" and the metadata-focused purpose indicate a Read operation. While the server offers execute_query tools that would be Execute or higher, this specific tool is limited to schema retrieval, making it a straightforward Read classification with low risk.
From the tool's definition Tool is named "retrieve_external_table_schema" and described as "Get the schema of an external table". Schema retrieval is a read-only operation that queries metadata without modifying, executing code, deleting data, or moving money.
Attacks that exploit this kind of access
Get the schema of an external table. It is categorised as a Read tool in the Kusto MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Kusto MCP Server MCP server in PolicyLayer and add a rule for retrieve_external_table_schema: 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 Kusto MCP Server. Nothing to install.
retrieve_external_table_schema 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 retrieve_external_table_schema 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 retrieve_external_table_schema. 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.
retrieve_external_table_schema is provided by the Kusto MCP Server MCP server (zzzhdw/mcp-server-kusto). 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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