diff --git a/CLAUDE.md b/CLAUDE.md
index b2f044a..1b54f6f 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -1,5 +1,7 @@
 # Reimbursement Form — Agent Reference
 
+> **Custom build** for [Boat People SOS](https://bpsos.org) and People Serving People Foundation. This branch (`bpsos-customisation`) contains org-specific configuration and any customisations made for those organisations.
+
 Static browser app that collects expense data via a form UI and generates a PDF with attached receipts. No server, no build step — one HTML file + config.yml + optional logo.
 
 ## Repository layout
diff --git a/README.md b/README.md
index 1f71759..e543382 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,7 @@
 # reimburse
- Static HTML reimbursement form. Auto-calculated totals, consistent output. Replaces error-prone Excel and PDF claims forms.
+
+Static HTML reimbursement form. Auto-calculated totals, consistent output. Replaces error-prone Excel and PDF claims forms.
+
+---
+
+**This branch (`bpsos-customisation`) is a custom build for [Boat People SOS](https://bpsos.org) and People Serving People Foundation.** It contains org-specific configuration and any customisations made for those organisations. For the generic upstream version, see the `main` branch.