The supplemental materials provide the full set of data and structured inputs used to implement the proposed collaborative risk assessment methodology. These materials are intended to support transparency and reproducibility for researchers seeking to understand or replicate the analysis. Specifically, the dataset includes: (1) original risk assessment inputs for two project segments, including cost impact ranges and likelihoods; (2) detailed prompt structures used to generate stakeholder-specific risk assessments; and (3) the resulting risk assessment inputs generated from prompt engineering for multiple stakeholders, including assigned weights, three-point cost estimates, and likelihood values across all risk events.