Cloud Services Providers (CSPs) deliver cloud services to cloud customers on a pay-per-use model. The quality of the provided services are defined using Service Level Agreements (SLAs). The recent developments around edge computing and the advent of mobile cloud computing platforms contribute to the success of this approach and the multiplication of offers. Unfortunately, despite the projections foreseeing a growing market for the coming years, there is no standard mechanism which exists to verify and assure that delivered services satisfy the signed SLA agreement. Accurate measures of the provided Quality of Service (QoS) is also missing most of time. In this context, we aim at offering an automatic framework named PRESENCE, to evaluate the QoS and SLA compliance of Web Services (WSs) offered across several CSPs. PRESENCE aims at quantifying in a fair and by stealth way the performance and scalability of the delivered WS. By stealthiness, we refer to the capacity of evaluating a given Cloud service by orchestrating multiple workload patterns that making them indistinguishable from a regular user traffic from the provider point of view. PRESENCE defines a set of Common performance metrics handled by a set of agents within a customized client (called the Auditor) for measuring the behaviour of cloud applications on top of a given CSP. This position paper offers a description of the PRESENCE framework, and the way each modules are foreseen to be designed. This opens novel perspectives for assessing the SLA compliance of Cloud providers using the PRESENCE framework.