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Enabling or Disabling Built-in Features

You can selectively enable or disable built-in tools, resources, and prompts; all features are enabled by default. When a feature is disabled:

- It is not advertised to the LLM in list operations
- Attempts to use it return an error message

Within the builtins section of the configuration file, you can indicate if you would like the feature to be enabled (true) or disabled (false):

builtins:
  tools:
    query_database: true        # Execute SQL queries
    get_schema_info: true       # Get schema information
    similarity_search: false    # Disable vector similarity search
    execute_explain: true       # Execute EXPLAIN queries
    generate_embedding: false   # Disable embedding generation
    search_knowledgebase: true  # Search documentation knowledgebase
    count_rows: true            # Count table rows
    llm_connection_selection: false  # LLM database switching (disabled by default)
  resources:
    system_info: true           # pg://system_info
  prompts:
    explore_database: true      # explore-database prompt
    setup_semantic_search: true # setup-semantic-search prompt
    diagnose_query_issue: true  # diagnose-query-issue prompt
    design_schema: true         # design-schema prompt

Notes

The read_resource tool is always enabled as it is required for listing resources.
Features can also be disabled by other configuration settings (e.g., search_knowledgebase requires knowledgebase.enabled: true).
The llm_connection_selection option is disabled by default for security. When enabled, it provides list_database_connections and select_database_connection tools that allow the LLM to switch between configured databases. Use allow_llm_switching: false on individual database connections to exclude them from LLM switching.

Using Environment Variables

Each built-in feature can also be toggled via an environment variable; this is convenient for containerized deployments where editing the configuration file is awkward. Environment variables take precedence over the configuration file.

Accepted truthy values are true, 1, and yes (case-insensitive); any other non-empty value is treated as false. If the variable is unset, the configuration file value (or the built-in default) is used.

Feature	Environment Variable
`query_database` tool	`PGEDGE_BUILTIN_TOOL_QUERY_DATABASE`
`get_schema_info` tool	`PGEDGE_BUILTIN_TOOL_GET_SCHEMA_INFO`
`similarity_search` tool	`PGEDGE_BUILTIN_TOOL_SIMILARITY_SEARCH`
`execute_explain` tool	`PGEDGE_BUILTIN_TOOL_EXECUTE_EXPLAIN`
`generate_embedding` tool	`PGEDGE_BUILTIN_TOOL_GENERATE_EMBEDDING`
`search_knowledgebase` tool	`PGEDGE_BUILTIN_TOOL_SEARCH_KNOWLEDGEBASE`
`count_rows` tool	`PGEDGE_BUILTIN_TOOL_COUNT_ROWS`
`llm_connection_selection` tools	`PGEDGE_BUILTIN_TOOL_LLM_CONNECTION_SELECTION`
`pg://system_info` resource	`PGEDGE_BUILTIN_RESOURCE_SYSTEM_INFO`
`explore-database` prompt	`PGEDGE_BUILTIN_PROMPT_EXPLORE_DATABASE`
`setup-semantic-search` prompt	`PGEDGE_BUILTIN_PROMPT_SETUP_SEMANTIC_SEARCH`
`diagnose-query-issue` prompt	`PGEDGE_BUILTIN_PROMPT_DIAGNOSE_QUERY_ISSUE`
`design-schema` prompt	`PGEDGE_BUILTIN_PROMPT_DESIGN_SCHEMA`

In the following example, the pg://system_info resource is disabled for a single container run:

PGEDGE_BUILTIN_RESOURCE_SYSTEM_INFO=false ./bin/pgedge-postgres-mcp