Background:
Social prescribing (SP) is an intervention that aims to improve patients' access to regional, voluntary, and state-funded services through an intermediate referral to a link worker (LW). In Austria, SP has been implemented in 24 primary care settings since 2019. As SP is a complex intervention, it requires a theoretical perspective to research its mechanism of action. Realist methods are suitable for this purpose, as they render implicit modes of operation explicit by establishing a programme theory (PT). The goal of this report was to summarise the available realist evidence on SP and integrate it into the Austrian SP-process, and address three specific topics.

Methods:
Our methodology was based on realist reviews, with relevant steps adapted due to limited time. The Austrian ideal model of SP was used as the initial PT. To answer the first research question (RQ1), context-mechanism-outcome configurations (CMOCs) were extracted from published realist studies and integrated into the Austrian SP ideal model. To answer RQ2, the CMOCs were coded according to three defined focus questions. Results were presented narratively.

Results:
RQ1: Each SP step should be understood as an intermediate outcome that must be achieved before the process can move forward, ultimately leading to the final outcomes. The SP-process begins with the identification of a non-medical health-related need in primary care. Whether a referral to a LW is made depends on internal factors of the provider and patient. However, successful participation in services depends on the diversity, accessibility, and suitability of the services.
RQ2: For vulnerable groups, an effective communication strategy and good accessibility of services are key. The workload of professionals with LW functions depends primarily on network management, the number of patients, and the time spent per patient. In addition, resources are needed for an SP database, LW training, and supervision.

Discussion & Conclusion:
The final PT demonstrates which aspects of SP are already underpinned by theoretical foundations and which require further research, such as the mechanisms of sensitisation, social acceptance of SP, and other potential endpoints. Furthermore, the PT provides a basis for planning future evaluations and selecting suitable monitoring indicators. However, the PT needs to be continuously developed further. Limitations include limited processing time and a reliance on studies from the United Kingdom. In conclusion, the developed PT is fundamental for the future development of SP in Austria.