Schema and metadata for a single table.
AI agents call describe_table to retrieve information from Mcp Bigquery Evals without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and returns schema information and metadata about a BigQuery table. It performs no side effects, does not modify data, does not execute queries against table contents, and does not trigger external operations.
From the tool's definition Tool name 'describe_table' and description 'Schema and metadata for a single table' indicate a retrieval operation that queries table metadata without modification or execution of business logic.
Attacks that exploit this kind of access
Schema and metadata for a single table. It is categorised as a Read tool in the Mcp Bigquery Evals MCP Server, which means it retrieves data without modifying state.
Register the Mcp Bigquery Evals MCP server in PolicyLayer and add a rule for describe_table: 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 Mcp Bigquery Evals. Nothing to install.
describe_table 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 describe_table 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 describe_table. 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.
describe_table is provided by the Mcp Bigquery Evals MCP server (umarfarook1/mcp-bigquery-evals). 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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