This replication package contains all materials used to evaluate how Large Language Models (LLMs) support scientific workflow development in Galaxy and Nextflow. It includes the full set of prompts, LLM responses, and generated workflows analyzed in the study. The package provides six PDF files: (1) LLMs’ understanding of fundamental scientific workflow and workflow-system concepts, and (2) their domain knowledge of Galaxy and Nextflow platforms, including architecture, key features, and reproducibility mechanisms. It also includes workflow-specific background questions for both systems, covering domain tasks such as SNP-rich exon detection, peak-to-gene association, methylation analysis, and QC pipelines. The package further provides the complete workflows generated by GPT-4o, Gemini 2.5 Flash, and DeepSeek-V3 for a set of benchmark tasks, detailing tool selections, execution steps, file transformations, and workflow structure. Together, these artifacts enable full transparency and reproducibility of our multi-dimensional assessment of LLMs’ conceptual reasoning, domain understanding, and workflow-generation capabilities across two major scientific workflow systems. The first two files provide foundational insights. The first file, Table-2 Fundamental_Concepts_Of_Scientific_Workflow_and_SWS, includes LLM-generated responses to conceptual questions about scientific workflows and workflow systems, evaluating the understanding of GPT-4o, Gemini 2.5 Flash, and DeepSeek-V3. The second file, Table-3 LLMs Understanding of Galaxy and Nextflow, further explores LLMs’ domain-specific knowledge by addressing background questions about the Galaxy and Nextflow platforms, including their architecture, tools, reproducibility, and key features such as Galaxy’s ToolShed or Nextflow’s DSL concepts and nf-core integration. The next two files, Table-4 and Table-5, contain workflow-specific background questions designed to assess LLM comprehension of domain-level specific tasks within Galaxy and Nextflow, respectively. These include tasks such as identifying SNP-rich exons, associating peaks with genes, or understanding methylation data processing. The final two files, LLMs Generated workflows using Galaxy Workflow System and LLMs generated workflows using Nextflow Workflow System, showcase the actual workflows generated by LLMs in response to structured prompts. Each file presents detailed, step-by-step workflows for different tasks, comparing how each LLM structures, sequences, and explains the analyses using real-world tools and formats (e.g., FastQC, BEDTools, MultiQC). These documents together form a multi-dimensional assessment of LLMs’ capability in generating, reasoning about, and structuring scientific workflows.