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 property graphs

list_property_graphs
Read-only

Lists SQL/PGQ property graphs defined in the database by reading information_schema.sql_property_graphs, returning schema, name, vertex and edge tables; empty on PG < 19 or missing catalog view.

Instructions

List SQL/PGQ property graphs defined in the database (reads information_schema.sql_property_graphs). Returns an empty list on PG < 19 or when the catalog view is missing (early Beta builds may not expose it yet — pair with get_pgq_status to disambiguate). Returns a list of objects with schema, name, vertex_tables (list of schema.table strings), and edge_tables (same shape).

Example: list_property_graphs()

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "list_property_graphs"
  }
}

Input Schema

NameRequiredDescriptionDefault
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

A4/5.0
Behavior4/5

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds genuinely non-obvious behavior: empty-list semantics on older versions and Beta builds, and the recommended disambiguation path with `get_pgq_status`. That is meaningful context beyond the annotations, though it doesn't discuss permissions or cost.

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?

Three sentences, front-loaded with the resource and source view, followed by the failure-mode caveat. The trailing zero-argument example is mildly redundant but short and does not obscure anything.

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?

An output schema exists, yet the description still restates the return fields, which is mild duplication. All the important gaps for a read-only listing tool — version-dependent emptiness and how to confirm it — are covered, so an agent can call it and interpret results correctly.

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

Parameters3/5

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

There is one optional `database` parameter with 100% schema description coverage, so the schema already explains targeting a secondary read-only database. The description says nothing about the parameter, which is acceptable at full coverage but adds no extra meaning (e.g., behavior when the target is not configured).

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 uses a specific verb+resource ('List SQL/PGQ property graphs') and names the exact catalog source (`information_schema.sql_property_graphs`), which implicitly separates it from generic graph listing. However, the sibling `list_graphs` is never mentioned, so an agent seeing both tools must infer the distinction (AGE-style graphs vs SQL/PGQ graphs) rather than being told.

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

Usage Guidelines4/5

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

It gives a concrete conditional instruction: an empty result on PG < 19 or a missing catalog view should be disambiguated by pairing with `get_pgq_status`. It stops short of explicitly stating when to prefer this over `list_graphs` or `describe_property_graph`, so sibling routing is only implied.

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