postgres-mcp

Instructions

Args:
    view_name: Name of the view
    schema: Schema name (default: public)
    
Returns:
    View definition SQL and column list

Implementation Reference

• postgres_mcp/postgres_client.py:392-432 (handler)

  Core handler function that executes the SQL queries to fetch view definition from information_schema.views and column details from information_schema.columns.

  def describe_view(self, view_name: str, schema: str = "public") -> dict[str, Any]:
      """Get view definition and columns.
      
      Args:
          view_name: View name
          schema: Schema name
          
      Returns:
          Dict with view definition and columns
      """
      result = {
          "name": view_name,
          "schema": schema,
          "definition": "",
          "columns": [],
      }
      
      with self.get_cursor() as cursor:
          # Get view definition
          cursor.execute("""
              SELECT view_definition
              FROM information_schema.views
              WHERE table_schema = %s AND table_name = %s
          """, (schema, view_name))
          row = cursor.fetchone()
          if row:
              result["definition"] = row["view_definition"]
          
          # Get columns
          cursor.execute("""
              SELECT 
                  column_name,
                  data_type,
                  is_nullable
              FROM information_schema.columns 
              WHERE table_schema = %s AND table_name = %s
              ORDER BY ordinal_position
          """, (schema, view_name))
          result["columns"] = [dict(row) for row in cursor.fetchall()]
      
      return result

• postgres_mcp/server.py:332-350 (registration)

  MCP tool registration using @mcp.tool() decorator. This is the entry point for the tool, which delegates to the PostgresClient instance and adds error handling and not-found response.

  @mcp.tool()
  @handle_db_error
  def describe_view(view_name: str, schema: str = "public") -> dict:
      """Get the definition and columns of a view.
      
      Args:
          view_name: Name of the view
          schema: Schema name (default: public)
          
      Returns:
          View definition SQL and column list
      """
      client = get_client()
      result = client.describe_view(view_name, schema)
      
      if not result["definition"]:
          return not_found_response("View", f"{schema}.{view_name}")
      
      return result