Professional-services work often depends on material supplied by the client: policies, spreadsheets, correspondence, contracts, reports, process notes or previous advice. The delivery team may receive those items through several channels and at different stages. A client source register gives the firm a controlled record of what arrived, where it came from and which version the team is actually using.
This is narrower than a general document-request list. A request list tracks what the firm still needs; a source register records material that has actually been received and may influence the work. Keeping that distinction clear helps teams avoid treating an expected document as though it were already part of the evidence base.
Register the source when it enters the engagement
Record important client-supplied material when it is received rather than trying to reconstruct provenance at the end. Give each source a recognisable description and capture the practical information needed to retrieve it, such as its supplied filename, date received and agreed storage location.
The register does not need to catalogue every routine email. Concentrate on sources that materially inform analysis, decisions, deliverables or assumptions.
Record provenance separately from file location
Where a file is stored is not the same as where it came from. Note the client contact, team, system or other authorised route through which the material was supplied when that provenance matters to interpretation.
This becomes particularly useful when similar files arrive from different stakeholders. The team can see not only which copy it has, but also the context in which that copy entered the engagement.
Make version relationships explicit
When an updated source arrives, connect it to the earlier version rather than creating an unrelated entry. Mark which version is current for the engagement and retain enough history to show what changed in the source set.
Avoid deleting the earlier reference merely because it has been superseded. Earlier work may have relied on it, and that history can help explain why a draft or decision took a particular form at the time.
State how the source is being used
A short relevance field can identify which workstream, deliverable or question the source informs. This prevents the register becoming a passive file inventory and helps another team member understand why a particular item matters.
If only part of a larger document is relevant, record that scope where useful. Reviewers should not have to infer that every statement in a supplied document has been adopted by the firm.
Flag limitations without altering the client's source
A source may be incomplete, provisional, undated or accompanied by qualifications. Record those limitations alongside the register entry rather than editing the supplied material to make it appear cleaner or more definitive.
Where a limitation creates a separate information gap, link the two working records. That keeps the provenance of the received source distinct from the action needed to resolve what is missing.
Control access according to the material involved
The register should point authorised team members towards the correct source without becoming a reason to duplicate sensitive material into unnecessary locations. Follow the firm's established access and information-handling arrangements and keep the register itself proportionate to the engagement.
If access changes during the work, update the location or access note rather than allowing colleagues to rely on obsolete instructions.
Reconcile the source register before finalising key work
At an appropriate review point, compare the register with the material actually relied upon. Confirm that current versions are identified, superseded sources are clear and important limitations remain visible.
A well-maintained client source register gives a small professional-services firm a dependable provenance trail. It helps the team answer what material it received, where it came from, which version mattered and how that source contributed to the engagement without reconstructing the story from scattered files.