list_functions
Discover functions and procedures in a PostgreSQL schema to understand available database operations and their signatures.
Instructions
List all functions and procedures in a schema.
Args:
schema: Schema name (default: public)
Returns:
List of functions with name, arguments, and return typeInput Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| schema | No | public |
Implementation Reference
- postgres_mcp/server.py:356-374 (handler)MCP tool handler and registration for 'list_functions'. This decorated function handles tool execution, delegates to PostgresClient, and formats output using FunctionSummary models.
@mcp.tool() @handle_db_error def list_functions(schema: str = "public") -> dict: """List all functions and procedures in a schema. Args: schema: Schema name (default: public) Returns: List of functions with name, arguments, and return type """ client = get_client() functions = client.list_functions(schema) return { "schema": schema, "functions": [FunctionSummary.from_row(f).model_dump() for f in functions], } - Core implementation in PostgresClient that executes the SQL query against pg_proc to retrieve function metadata from the database.
def list_functions(self, schema: str = "public") -> list[dict]: """List functions and procedures in a schema. Args: schema: Schema name Returns: List of function dicts """ query = """ SELECT p.proname AS routine_name, n.nspname AS routine_schema, pg_get_function_result(p.oid) AS return_type, pg_get_function_arguments(p.oid) AS argument_types, CASE p.prokind WHEN 'f' THEN 'function' WHEN 'p' THEN 'procedure' WHEN 'a' THEN 'aggregate' WHEN 'w' THEN 'window' ELSE 'unknown' END AS routine_type FROM pg_proc p JOIN pg_namespace n ON n.oid = p.pronamespace WHERE n.nspname = %s AND p.proname NOT LIKE 'pg_%' ORDER BY p.proname """ with self.get_cursor() as cursor: cursor.execute(query, (schema,)) return [dict(row) for row in cursor.fetchall()] - postgres_mcp/models.py:183-201 (schema)Pydantic model defining the output schema for function summaries, used in the tool response for type validation and serialization.
class FunctionSummary(BaseModel): """Function/procedure info.""" name: str schema_name: str = "public" return_type: Optional[str] = None argument_types: str = "" func_type: str = "function" # function, procedure, aggregate @classmethod def from_row(cls, row: dict) -> "FunctionSummary": return cls( name=row.get("routine_name", row.get("proname", "")), schema_name=row.get("routine_schema", row.get("nspname", "public")), return_type=row.get("data_type", row.get("return_type")), argument_types=row.get("argument_types", ""), func_type=row.get("routine_type", "function").lower(), )