Lee Killough’s 1980 The Monitor, the Miners, and the Shree is a standalone hard SF novel.
Unlike the Galactic Union, the Sodality that has replaced the Union has a strict no-contact rule where pre-spaceflight worlds are concerned. Thus, when the Sodality discovered that there was a previously unnoticed low-tech species on planet Nira, they forced the Megeyn mining company to shut down operations on Nira and leave the native Shree to develop in isolation.
The Sodality likes to keep an eye on developing worlds. Once every five hundred years, the Department of Surveys and Charters (DSC) dispatches a team of scientists to secretly monitor the Shree. Newly minted monitor Chemel Krar is in charge of the latest team. It is her task to ensure that the scientists hired by DSC do not violate the no-contact rule while spying on the natives.
The expedition goes wrong surprisingly quickly.