list_tables

List tables in schema

Server PostgreSQL MCP Server psreekrishnan/postgresql-mcp
Category Read
Risk class Low
Parameters 00 required

What list_tables does on PostgreSQL MCP Server

AI agents call list_tables to retrieve information from PostgreSQL MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

Why list_tables needs a policy

This tool retrieves schema metadata (table names) without modifying, executing code, or affecting data. It is a straightforward read operation with minimal blast radius - listing tables cannot cause harm even if misused. The server itself is explicitly designed for read-only access with automatic row limits, confirming this is a safe informational query.

From the tool's definition Tool description states 'List tables in schema' - a pure read operation that retrieves metadata. Server description emphasizes 'secure, read-only access' and states the server provides capabilities for 'querying data, listing tables, and describing schemas'…

Questions about list_tables

What does the list_tables tool do? +

List tables in schema. It is categorised as a Read tool in the PostgreSQL MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on list_tables? +

Register the PostgreSQL MCP Server MCP server in PolicyLayer and add a rule for list_tables: 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 PostgreSQL MCP Server. Nothing to install.

What risk level is list_tables? +

list_tables is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit list_tables? +

Yes. Add a rate_limit block to the list_tables 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.

How do I block list_tables completely? +

Set action: deny in the PolicyLayer policy for list_tables. 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.

What MCP server provides list_tables? +

list_tables is provided by the PostgreSQL MCP Server MCP server (psreekrishnan/postgresql-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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