Skip to main content
Glama
Sign In
MCPg - Production-grade PostgreSQL MCP Server

MCPg - Production-grade PostgreSQL MCP Server

by devopam
OverviewSchemaSourceRelated ServersDiscussionsAdmin
Python
Hybrid

List foreign tables

list_foreign_tables
Read-only

Retrieve foreign tables in a PostgreSQL schema with each table's foreign server and options, so agents can inspect external table definitions and dependencies.

Instructions

List the foreign tables in a schema, with their server and options. Returns a list of objects with name, server (foreign-server name), and options (dict of per-table options).

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "schema": "<schema>"
    },
    "name": "list_foreign_tables"
  }
}

Input Schema

NameRequiredDescriptionDefault
schemaYes
databaseNoOptional: a database id from list_databases, to target a configured secondary (read-only) database; omit for the primary. Database names that are not configured ids are rejected.

Output Schema

NameRequiredDescriptionDefault
resultYes

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed1 schema field changedv0.8.4
    • changedInput schema / properties / database / description
      Previous value: -"Optional: target a configured secondary (read-only) database by name; omit for the primary. Call list_databases to see the configured ids."New value: +"Optional: a database id from list_databases, to target a configured secondary (read-only) database; omit for the primary. Database names that are not configured ids are rejected."
  2. First observedv0.6.8

TDQS

A3.7/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds the return shape (name, server, options), but that duplicates the output schema rather than adding new behavioral context. Nothing is said about behavior when the schema is absent or contains no foreign tables.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, zero waste, with the purpose front-loaded and the return shape trailing. Every clause carries information and there is no filler or restatement of the title.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With annotations covering the safety profile and an output schema defining the returned fields, the description needs to establish purpose and scope only, which it does. The remaining gap is behavioral edge cases (missing schema, empty results), minor for a read-only listing tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is only 50%, and the undocumented parameter is the required `schema`, which the description covers by stating the listing is scoped to a schema. The description adds no detail beyond that, leaving format expectations (e.g., exact name vs. search path) unstated. Baseline for partial coverage would be 3; the description compensates only for the required parameter, so 3-4 is warranted.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a specific verb and resource ("List the foreign tables in a schema") and adds scope detail (per-server, per-table options). It doesn't explicitly distinguish itself from nearby siblings like list_foreign_servers or list_foreign_data_wrappers, but the resource is distinct enough that an agent can select it without opening the schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is only implicit: an agent can infer this is the introspection tool for foreign tables within a given schema. There is no explicit when-to-use guidance, no statement of when to prefer list_foreign_servers or list_user_mappings instead, and no mention of prerequisites such as the schema needing to contain foreign tables.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Deploy Server

Other Tools