Confidentiality letter (pre-contract advice to a contractor)
A confidentiality letter from a professional consultant to a contractor, for use prior to and during the tender process on a construction or engineering project. Although written from the professional consultant to the contractor, it is usually generated by the contractor.
The agreement is written as a letter requiring the professional consultant to treat information and documents provided by the contractor as confidential.
In other legal contexts, the letter may be described as a non-disclosure agreement (NDA).