List all non-system schemas in the database with their owners.
AI agents call list-schemas to retrieve information from Tusk without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs schema introspection to retrieve metadata about database schemas and their owners. It has no side effects, cannot modify data, and is explicitly part of a read-only server. Classification as Read is appropriate with low severity due to minimal blast radius if misused—at worst, an agent gains visibility into schema structure.
From the tool's definition Tool name 'list-schemas' and description 'List all non-system schemas in the database with their owners' indicate retrieval/introspection operations only. Server description confirms 'read-only PostgreSQL MCP server' with 'SELECT-only queries'.
Documented attack patterns abuse exactly the kind of access list-schemas gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Tusk, and nothing reaches the server without passing your rules. This is the rule we recommend for list-schemas:
{
"version": "1",
"default": "deny",
"tools": {
"list-schemas": {}
}
}list-schemas is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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List all non-system schemas in the database with their owners. It is categorised as a Read tool in the Tusk MCP Server, which means it retrieves data without modifying state.
Register the Tusk 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 Tusk. Nothing to install.
list-schemas 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 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.
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.
list-schemas is provided by the Tusk MCP server (volveezz/tusk-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Tusk, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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4 Tusk tools catalogued and risk-classified — across an index of 43,000+ MCP servers.