List all constraints for a table (foreign keys, primary keys, unique, check)
AI agents call postgres_list_constraints to retrieve information from Multi-Database MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries database schema information (constraints metadata) with no side effects. It is a read-only operation that retrieves existing data structures without altering them, executing code, or affecting financial systems. The low severity reflects that constraint metadata is typically non-sensitive schema information, though confidence is high given the clear read-only nature of the operation.
From the tool's definition Tool name contains 'list' and description states 'List all constraints' - purely retrieves schema metadata without modification or execution. No delete, update, insert, or execute operations.
Attacks that exploit this kind of access
List all constraints for a table (foreign keys, primary keys, unique, check). It is categorised as a Read tool in the Multi-Database MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Multi-Database MCP Server MCP server in PolicyLayer and add a rule for postgres_list_constraints: 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 Multi-Database MCP Server. Nothing to install.
postgres_list_constraints 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 postgres_list_constraints 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 postgres_list_constraints. 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.
postgres_list_constraints is provided by the Multi-Database MCP Server MCP server (nam088/mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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