list_schemas

List all schemas in the current database.

SERVERPostgreSQL MCP Server SOURCEaeiyannn/postgree-mcp

Low RISK CLASS

Category Read

Parameters 00 required

Recommended Allowedsee the rule below

Registry record Grade C, identity unverified Pull the record →

This record as markdown: /tools/aeiyannn-postgree-mcp/list-schemas.md

WHAT IT DOES

What list_schemas does on PostgreSQL MCP Server

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

RISK

Why list_schemas is rated Low

This tool queries database metadata to enumerate schemas. It performs read-only introspection with no ability to modify, delete, or execute operations. The blast radius of misuse is minimal; an agent listing schemas gathers information but cannot alter the database or trigger external effects. Severity is low because schema enumeration is a standard, safe administrative query.

From the tool's definition Tool name is 'list_schemas' and description states 'List all schemas in the current database' — a retrieval operation with no side effects.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs list_schemas safely

PolicyLayer is an MCP gateway: it sits between your AI agents and PostgreSQL MCP Server, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For list_schemas, this is the rule to start with:

list_schemas Allowed

list_schemas is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "list_schemas": {}
  }
}

ALLOW ONLY THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect PostgreSQL MCP Server, apply this rule, and every list_schemas call is checked against it from then on.

FAQ

Questions about list_schemas

What does the list_schemas tool do? +

List all schemas in the current database. 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_schemas? +

Register the PostgreSQL MCP Server MCP server in PolicyLayer and add a rule for list_schemas: 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_schemas? +

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

Can I rate-limit list_schemas? +

Yes. Add a rate_limit block to the list_schemas 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_schemas completely? +

Set action: deny in the PolicyLayer policy for list_schemas. 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_schemas? +

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

KEEP EXPLORING

What list_schemas does on PostgreSQL MCP Server

Why list_schemas is rated Low

The rule that runs list_schemas safely

Questions about list_schemas

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