Get all table constraints (CHECK, UNIQUE, PRIMARY KEY, FOREIGN KEY).
AI agents call PostgreSQL_get_all_constraints to retrieve information from Postgres without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and returns constraint information from a PostgreSQL database without modifying, deleting, or executing any operations. It is a read-only introspection operation that retrieves schema metadata. The blast radius of misuse is minimal—an agent could gather schema information but cannot alter database structure or data.
From the tool's definition Tool name and description indicate retrieval of constraint metadata: 'Get all table constraints' with no mention of modification, deletion, or execution capabilities. Returns data about CHECK, UNIQUE, PRIMARY KEY, and FOREIGN KEY constraints.
Documented attack patterns abuse exactly the kind of access PostgreSQL_get_all_constraints gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Postgres, and nothing reaches the server without passing your rules. This is the rule we recommend for PostgreSQL_get_all_constraints:
{
"version": "1",
"default": "deny",
"tools": {
"PostgreSQL_get_all_constraints": {}
}
}PostgreSQL_get_all_constraints is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Get all table constraints (CHECK, UNIQUE, PRIMARY KEY, FOREIGN KEY). It is categorised as a Read tool in the Postgres MCP Server, which means it retrieves data without modifying state.
Register the Postgres MCP server in PolicyLayer and add a rule for PostgreSQL_get_all_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 Postgres. Nothing to install.
PostgreSQL_get_all_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 PostgreSQL_get_all_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 PostgreSQL_get_all_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.
PostgreSQL_get_all_constraints is provided by the Postgres MCP server (mukul975/postgres-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Postgres, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
239 Postgres tools catalogued and risk-classified — across an index of 43,000+ MCP servers.