Building commissioning is a method or long-term process for quality assurance of construction works, proving building systems operability and correct functionality. The activities of the person managing the Cx process - Commissioning authority / agent (CxA) - complement the activities of the investor's technical supervisor (TDS from Czech "Technický dozor stavebníka") according to practices in the Czech Republic. It is also possible to recognise activities of the TDS as a subset of building commissioning activities. Ideally, the CxA acts as an advisor to the investor / owner during the project briefing in order to include building systems operational and functional requirements. The Cx process should start prior to the concept study and end during the first years of building use. When an owner of the project is choosing the CxA, they should pay particular attention to defining how quality assurance and quality control would be addressed during construction and installation works. Good Cx process includes but is not limited to the following: _developing the OPR (Owner's Project Requirements), _developing the BOD (Basis of Design), _specifying required activities for tendering roles throughout the project, _developing a Commissioning Plan, _describing Functional Performance Tests (FPT) _warranty conditions, _and lessons learnt.

Designers, contractors, and other selected construction participants are an integral part of the commissioning team, as their work directly impacts the quality, functionality, and long-term sustainability of the building. Involving these parties in the Cx process early and with clearly specified requirements contributes to a smoother construction process and minimises problems. The Commissioning Authority (CxA) works together with designers and contractors from the early stages of the project to ensure that the technical solutions and construction execution comply with the OPR (Owner’s Project Requirements) and BOD (Basis of Design). The CxA also helps coordinate activities among various participants to meet quality and operational performance requirements. The main benefits and activities of the Cx process for designers, contractors, and other construction participants include the following: _early coordination of operational and functional requirements within the project documentation, reducing the risk of later changes and rework, _clearly defined roles, responsibilities, and requirements within the Cx process, reducing the risk of misunderstandings among construction participants, _quality control during construction by the contractor, including compliance with specifications, standards, and manufacturers’ instructions, as well as thorough inspection from components to complete systems, _execution of Functional Performance Tests (FPT) to verify that all building systems (e.g., HVAC, electrical installations, domestic hot water systems) operate according to design, _handover of complete documentation (e.g., inspection reports, manuals, and system operating procedures) by contractors and designers, forming part of the Cx process and serving future operation and maintenance needs.

In some cases, the Cx process is referred to in the Czech Republic as the operator's technical supervision, in order to better reflect the emphasis on the operational functionality of the building. The difference is also noticeable in the public sector, where the investment department manages the design and construction of the building and the economic department manages the operation and use. These two departments should cooperate and even be able to share financial and human resources to avoid situations with the absence of a suitable solution. And if a situation arises without a way out, the so-called retro-commissioning of the building should take place, when the operational state becomes economical, even assuming the loss of some guarantees or warranties. The team responsible for the management, operation and maintenance of the building should be active already during the design, construction and commissioning of the building. However, it happens that the persons are not yet appointed at that time, and therefore the CxA usually defends their interests and ensures the collection of useful information. A good Cx process includes, among others, the following: _keeping lists of topics and issues related to building systems included in the Cx process, _creating a building operator's manual/building manual, _ensuring quality operator training, _preparing an Operations and Maintenance Plan.