AI agents call psql-list-databases to retrieve information from Python without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a read-only operation on a PostgreSQL server, returning informational data about existing databases. There are no side effects, no data modifications, no code execution, and no destructive actions. The blast radius of misuse is minimal—an agent could gather information about available databases but cannot alter, delete, or interact with database contents through this tool alone.
From the tool's definition Tool name 'psql-list-databases' and description 'Lists all PostgreSQL databases' indicates a query operation that retrieves database metadata (owner, encoding, size) without modifying or executing code.
Attacks that exploit this kind of access
Lists all PostgreSQL databases via psql with owner, encoding, and size info. It is categorised as a Read tool in the Python MCP Server, which means it retrieves data without modifying state.
Register the Python MCP server in PolicyLayer and add a rule for psql-list-databases: 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 Python. Nothing to install.
psql-list-databases 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 psql-list-databases 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 psql-list-databases. 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.
psql-list-databases is provided by the Python MCP server (Dave-London/Pare). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
psql-list-databases is one line of Python's registry record.
The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.
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