What is staff augmentation?
Staff augmentation is an arrangement where a client adds external specialists to its own teams, working alongside its employees, under its own project plan, while those specialists remain employed or contracted by the supplier. The client gains capacity without hiring.
It is the most widely used consulting model in the Belgian technology market, and it is also the one with the most legal exposure attached to it. That exposure is not exotic. It is the ordinary way the model fails.
Why does staff augmentation carry legal risk in Belgium?
Because of the rules on lending personnel. Under the law of 24 July 1987, putting workers at the disposal of a third party who exercises any part of the authority normally belonging to the employer is prohibited outside temporary agency work and a small number of authorised cases. The SPF Emploi guidance on making workers available to a user sets out the principle and its exceptions.
The sanctions are the reason it matters. Where the prohibition is breached, the worker is deemed bound to the user by an employment contract of indefinite duration from the start of the work, and the user and the supplier become jointly liable for social security contributions, pay, indemnities and benefits. A capacity arrangement can become a permanent employment relationship the client never agreed to.
What instructions can a client actually give?
Two categories, and the distinction is precise. Instructions relating to the client's welfare and safety obligations at its own site are explicitly not an exercise of employer authority, so those can always be given.
Everything else needs a written agreement between the client and the supplier that states precisely which instructions the client may give, with actual practice matching what the document says. The client must also inform its works council of that agreement and provide a copy of the instructions clause, or in its absence the prevention committee or union delegation. Day-to-day technical coordination is workable. Deciding someone's working hours, approving their leave, running their appraisal or moving them to another project is not, because those are employer decisions.
How is staff augmentation different from secondment and interim work?
The three sit on a spectrum of who holds authority. Interim work is the regulated route for genuine lending: an agency employs the worker, the user directs them, and the law permits it because the framework for temporary agency work says so.
Secondment and staff augmentation both keep the worker under the supplier's authority, which is what makes them lawful outside that framework, and what makes the written instruction clause load-bearing rather than administrative. The practical test is not what the contract is called. It is who decides what the person works on next week. Sparagus places consultants it employs directly through its project delivery and consulting engagements.
