Run a SQL query against BigQuery and return results. Only SELECT queries are allowed. A LIMIT clause is automatically added if missing. Claude should use list_datasets, list_tables, and describe_table first to understand the schema before writing queries.
AI agents call query 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.
Despite being named 'query', this tool is restricted to SELECT operations, which are read-only data retrievals with no side effects. The automatic LIMIT clause further reduces risk of excessive data exposure. No data modification, deletion, or code execution is permitted. This is a straightforward Read category tool with low severity due to its query-only constraint.
From the tool's definition Tool description explicitly states 'Only SELECT queries are allowed' and 'A LIMIT clause is automatically added if missing.' SELECT queries retrieve data without modification.
Documented attack patterns abuse exactly the kind of access query 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 query:
{
"version": "1",
"default": "deny",
"tools": {
"query": {}
}
}query is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Run a SQL query against BigQuery and return results. Only SELECT queries are allowed. A LIMIT clause is automatically added if missing. Claude should use list_datasets, list_tables, and describe_table first to understand the schema before writing queries. 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 query: 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.
query 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 query 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 query. 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.
query 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.