describe_table

Detail the columns, types, and primary keys of a specific table (FR-002)

SERVERPostgres SOURCE@allensandiego/postgres-mcp-server

Low RISK CLASS

Category Read

Parameters 22 required

Recommended Allowedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/allensandiego-postgres-mcp-server/describe-table.md

WHAT IT DOES

What describe_table does on Postgres

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

Parameter	Type	Required	Description
`table`	string	Yes	Table name
`schema`	string	Yes	Schema name (e.g. 'public')

Parameters from the server's own tool schema.

RISK

Why describe_table is rated Low

Even though describe_table only reads data, uncontrolled read access leaks sensitive information and racks up API costs: an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs describe_table safely

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

describe_table Allowed

describe_table 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": {
    "describe_table": {}
  }
}

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

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

FAQ

Questions about describe_table

What does the describe_table tool do? +

Detail the columns, types, and primary keys of a specific table (FR-002). It is categorised as a Read tool in the Postgres MCP Server, which means it retrieves data without modifying state.

What parameters does describe_table accept? +

describe_table accepts 2 parameters: table, schema. Required: table, schema. The full parameter table on this page comes from the server's own tool schema.

How do I enforce a policy on describe_table? +

Register the Postgres MCP server in PolicyLayer and add a rule for describe_table: 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.

What risk level is describe_table? +

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

Can I rate-limit describe_table? +

Yes. Add a rate_limit block to the describe_table 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 describe_table completely? +

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

describe_table is provided by the Postgres MCP server (@allensandiego/postgres-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

What describe_table does on Postgres

Why describe_table is rated Low

The rule that runs describe_table safely

Questions about describe_table

More on Postgres, and thousands of servers like it.