Run a raw DQL SQL query, like SELECT, SHOW, DESCRIBE, EXPLAIN, etc.
AI agents call run_dql_query to retrieve information from Pgsql without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
DQL (Data Query Language) operations such as SELECT, SHOW, DESCRIBE, and EXPLAIN only retrieve data without modifying it, placing this firmly in the Read category. Severity is medium rather than low because unrestricted raw SQL queries against a PostgreSQL database could expose sensitive data across all schemas and tables, representing a meaningful data exfiltration risk if misused.
From the tool's definition Run a raw DQL SQL query, like SELECT, SHOW, DESCRIBE, EXPLAIN, etc.
Documented attack patterns abuse exactly the kind of access run_dql_query gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Pgsql, and nothing reaches the server without passing your rules. This is the rule we recommend for run_dql_query:
{
"version": "1",
"default": "deny",
"tools": {
"run_dql_query": {}
}
}run_dql_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 raw DQL SQL query, like SELECT, SHOW, DESCRIBE, EXPLAIN, etc. It is categorised as a Read tool in the Pgsql MCP Server, which means it retrieves data without modifying state.
Register the Pgsql MCP server in PolicyLayer and add a rule for run_dql_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 Pgsql. Nothing to install.
run_dql_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 run_dql_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 run_dql_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.
run_dql_query is provided by the Pgsql MCP server (twn39/pgsql-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Pgsql, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
9 Pgsql tools catalogued and risk-classified — across an index of 43,000+ MCP servers.