Abstract Background Mental health issues are highly prevalent among precarious workers, often leading to sickness absence, work disability, and job loss. Return to work (RTW) is more challenging for these workers, as they often lack a job to return to and have limited access to occupational health care. Perceptions and attitudes about RTW are important determinants and can be categorized into three modes within the RTW process: a passive, an ambivalent and an active RTW-mode. To identify the RTW mode, we developed the RE-MODE tool. This study aimed to assess occupational health professionals’ agreement on the RTW-mode of sick-listed precarious workers with mental health issues using RE-MODE. Methods In a vignette study, 71 occupational health professionals from a Dutch social security institute viewed six videos of consultations between insurance physicians and precarious workers. They then used RE-MODE to assess the RTW mode and need for RTW-support. They also provided feedback on the tool’s validity and usability. We used a generalized linear mixed model to analyze inter-rater agreement, inter-item consistency, and the contribution level of each item. Additionally, we calculated the content validity index and the system usability scale. Results The agreement on the RTW mode with RE-MODE is high (ICC 0.86, 95% CI 0.64-0.95) and on the workers’ need for RTW-support moderate (0.61, 95% CI 0.31-0.84). Furthermore, the content-validity (Scale-CVI 0.83), usability (SUS 0.75), and inter-item consistency (Cronbach’s Alpha 0.70) show favorable results. We are currently analyzing the contribution of each item to the total score. The items with the best overall performance will be included in RE-MODE 2.0. Conclusions REMODE is a valuable tool for occupational health professionals to identify precarious workers with mental health issues at risk of long-term disability. Then they can arrange targeted RTW-support. Based on the study results, RE-MODE 2.0 is in development. Key messages • RE-MODE is a valuable tool for the assessment of the RTW-mode of precarious workers with mental health issues. • RE-MODE’s reliability, content-validity and usability is satisfactory.