Get detailed schema information for a specific BigQuery table including column names, types, descriptions, row count, size, partitioning, and clustering.
AI agents call describe_table to retrieve information from BigQuery MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool purely retrieves and queries metadata about BigQuery table schemas. It has no side effects, does not modify data, does not execute arbitrary queries or code, and does not delete anything. It is a straightforward introspection/discovery tool, appropriate for an AI agent to use safely to understand data structure before querying.
From the tool's definition Tool description states it 'Get[s] detailed schema information' and retrieves metadata including 'column names, types, descriptions, row count, size, partitioning, and clustering' — all read-only operations with no modification, deletion, or execution of code.
Documented attack patterns abuse exactly the kind of access describe_table gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and BigQuery MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for describe_table:
{
"version": "1",
"default": "deny",
"tools": {
"describe_table": {}
}
}describe_table is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Get detailed schema information for a specific BigQuery table including column names, types, descriptions, row count, size, partitioning, and clustering. It is categorised as a Read tool in the BigQuery MCP Server MCP Server, which means it retrieves data without modifying state.
Register the BigQuery MCP Server 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 BigQuery MCP Server. 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 BigQuery MCP Server MCP server (suganthan-mohanadasan/suganthans-bigquery-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 32 BigQuery MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
32 BigQuery MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.