list_schemas

List all schemas in the database

Server Fluid Postgres povesma/fluid-postgres-mcp
Category Read
Risk class Low
Parameters 00 required

What list_schemas does on Fluid Postgres

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

Why list_schemas needs a policy

This tool retrieves structural metadata from the database without creating, modifying, deleting, or executing any code. It is a straightforward informational query with minimal blast radius if misused by an AI agent—an attacker could learn the database structure but cannot manipulate data or resources. Severity is low because schema names are typically non-sensitive metadata and enumeration alone poses minimal risk.

From the tool's definition Tool name 'list_schemas' and description 'List all schemas in the database' indicate a query/retrieval operation that returns metadata about database schemas.

Questions about list_schemas

What does the list_schemas tool do? +

List all schemas in the database. It is categorised as a Read tool in the Fluid Postgres MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on list_schemas? +

Register the Fluid Postgres 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 Fluid Postgres. 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 Fluid Postgres MCP server (povesma/fluid-postgres-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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