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MCP Resources

Resources provide read-only access to PostgreSQL system information. Resources are accessed via the read_resource tool or through MCP protocol resource methods.

Disabling Resources

Individual resources can be disabled via configuration to restrict what the LLM can access. See Enabling/Disabling Built-in Features for details.

When a resource is disabled:

  • It is not advertised to the LLM in the resources/list response
  • Attempts to read it return an error message

Available Resources

pg://system_info

Returns PostgreSQL version, operating system, and build architecture information. Provides a quick and efficient way to check server version and platform details without executing natural language queries.

Access: Read the resource to view PostgreSQL system information.

Output: JSON object with detailed system information:

{
  "postgresql_version": "15.4",
  "version_number": "150004",
  "full_version": "PostgreSQL 15.4 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 11.2.0, 64-bit",
  "operating_system": "linux",
  "architecture": "x86_64-pc-linux-gnu",
  "compiler": "gcc (GCC) 11.2.0",
  "bit_version": "64-bit"
}

Fields:

  • postgresql_version: Short version string (e.g., "15.4")
  • version_number: Numeric version identifier (e.g., "150004")
  • full_version: Complete version string from PostgreSQL version() function
  • operating_system: Operating system (e.g., "linux", "darwin", "mingw32")
  • architecture: Full architecture string (e.g., "x86_64-pc-linux-gnu", "aarch64-apple-darwin")
  • compiler: Compiler used to build PostgreSQL (e.g., "gcc (GCC) 11.2.0")
  • bit_version: Architecture bit version (e.g., "64-bit", "32-bit")

Use Cases:

  • Quickly check PostgreSQL version without natural language queries
  • Verify server platform and architecture
  • Audit server build information
  • Troubleshoot compatibility issues

Accessing Resources

Resources can be accessed in two ways:

1. Via read_resource Tool

{
  "uri": "pg://system_info"
}

Or list all resources:

{
  "list": true
}

2. Via Natural Language (Claude Desktop)

Simply ask Claude to read a resource:

System Information:

  • "Show me the output from pg://system_info"
  • "What's the current PostgreSQL version?" (uses pg://system_info)
  • "What version of PostgreSQL is running?" (uses pg://system_info)

Schema Information

For database schema information (tables, columns, constraints, etc.), use the get_schema_info tool instead of resources. It provides:

  • Detailed column information with data types
  • Primary key, foreign key, and unique constraints
  • Index information
  • Identity column detection
  • Default values
  • Vector column detection for similarity search
  • TSV output format for token efficiency

See Tools Reference for details.