Short answer: include the service, project type, inputs, software and formats, standards, approximate scope and target dates. Flag unknowns early.
The more clearly a requirement is described, the faster and more accurately it can be scoped. You do not need everything on day one. If the scope is still being defined, it is fine to get in touch first.
The essentials
- Service required and project type.
- Available inputs: drawings, models, point clouds, photos.
- Software and file requirements, including versions.
- Relevant standards, templates and naming conventions.
- Approximate quantity or scope: area, floors, disciplines, elements.
- Target timeline and review points.
Describe the outputs
State what you need to receive: native models, exchange formats, sheets, schedules or review notes. Say how the outputs will be used. That usually decides the level of detail more than anything else.
Flag the unknowns
Missing drawings, partial scans or open design decisions are normal. Listing them early allows assumptions to be agreed rather than discovered later.
Protect confidential information
Avoid sending confidential files until a suitable transfer and confidentiality process has been agreed. A short description and a sample are usually enough to begin.