arXiv:2610.37283v1 Announce Type: new Abstract: Software-engineering research relies on benchmarks that evaluate new techniques on a set of problem instances. Unfortunately, manually constructing benchmarks is labor-intensive, as researchers must find suitable instances, prepare execution environments, establish expected outcomes, and validate correctness. This paper presents BenchMeUp, an approach for automatically creating software-engineering benchmarks from natural-language specifications. Given a specification defining the desired instances, data sources, and evaluation procedures, BenchMeUp generates search rules and a construction plan, invokes parallel LLM agents that identify candidate instances and construct executable instances, validates the results in fresh execution environments, and packages the instances behind a unified command-line interface. We evaluate the approach on four tasks: program repair, issue reproduction, compiler autotuning, and fixing static-analysis warnings. Targeting 50 instances per task (200 in total), BenchMeUp constructs 198 instances, of which 196 (99\%) are successfully packaged. Search and construction take 36 minutes and \$0.79 per instance, on average. Evaluating eight existing techniques on the generated benchmarks, we find that 189 of 196 packaged instances (96\%) support end-to-end evaluation, allowing users to study the effectiveness of the techniques. Checking every constructed instance against its source, the specification, and its expected outcome, we find that 180 of 198 (91\%) meet all criteria, compared with 10 of 200 instances delivered by Codex (general-purpose coding agent). Overall, we show that LLM-based agents can automate benchmark construction across diverse software-engineering tasks and produce executable instances that existing techniques can use, while validity beyond execution still needs to be checked.