The purpose of this educational intervention was to introduce, iteratively adapt, and implement a digital formative assessment tool in a surgical speciality. The study also evaluated the intervention's impact on perioperative teaching, learning, feedback, and surgical competency. A participatory action research model with a mixed methods approach. This study was performed over 10 months in an institutional hospital in South Africa with a general surgery department. Twelve supervising surgical trainers/faculty and 12 surgical trainees/residents consented to participate in the intervention. The first 4 months of the intervention focused on relationship building, a multi-stakeholder contextual needs assessment and training sessions to support a shared mindset and shift in the teaching and learning culture. The final adapted perioperative competency-building tool comprised a 23-item assessment with four open-text answers (Table 1). Over the following 6-month period, 48 workplace-based competency-building perioperative evaluations were completed. Most trainees took less than 5 minutes to self-assess (67%) before most trainers (67%) took less than 5 minutes to give oral feedback to the trainee after the perioperative supervised learning encounter. On average, the digital tool took 6 minutes to complete during the bidirectional perioperative teaching and learning encounter with no negative impact on the operational flow. All trainers and trainees reported the training and implementation of the digital tool to be beneficial to teaching, learning, feedback, and the development of surgical competency. Analysis of the completed tools revealed several trainees showing evidence of progression in surgical competency for index procedures within the speciality. The focus groups and interviews also showed a change in the teaching and learning culture: more positively framed, frequent, structured, and specific feedback, improved accountability, and trainee-trainer perioperative readiness for teaching. Highlighted changes included the usefulness of trainee self-assessment before perioperative trainer feedback and the tool's value in improving competency to Kirkpatrick Level 4. Implementing an adapted digital Workplace-Based Assessment (WBA) tool using a participatory action research model has proven successful in enhancing the effectiveness of supervised perioperative teaching and learning encounters. This approach has improved teaching and feedback practices, facilitated the development of surgical competency, and ultimately impacted the overall culture to Kirkpatrick level 4. Importantly, it has positively influenced the trainee-trainer relationship dynamic. Based on these positive outcomes, we recommend using this effective method and our relationship-centred framework for implementing formative competency-building tools in future studies. By doing so, larger-scale and successful implementation of Competency-Based Medical Education (CBME) could be achieved in various contexts. This approach can potentially enhance teaching and learning encounters, promote competency development, and improve the overall educational experience for surgical trainees and trainers.