One possible distinction is: does the work reveal anything beyond the solution itself? The work might, for example, give one instance of a class of problems for

One possible distinction is: does the work reveal anything beyond the solution itself? The work might, for example, give one instance of a class of problems for which the tool is useful (bonus points for a formal statement to that effect). Or improve the tool, or improve understanding of the tool’s strengths and weaknesses I think this is what we try to capture as “expanding human knowledge”. IMO the more isolated the result (“technique x gave good results for problem y, the end”), the less like “research” it is. Though plenty such papers get into good conferences every year. A nice story and a little reviewer luck go a long way.