diff --git a/expenses/views.py b/expenses/views.py
index 7d1bd00..134e854 100644
--- a/expenses/views.py
+++ b/expenses/views.py
@@ -131,8 +131,18 @@ def expense_create(request):
             receipts = request.FILES.getlist('receipt')
             if receipts:
                 from .models import Document
-                for f in receipts:
-                    Document.objects.create(expense=expense, file=f, title=f.name, uploaded_by=request.user)
+                import os
+                cat_name = expense.category.name if expense.category else 'Evidencia'
+                proj_code = expense.project.code if expense.project else 'PROY'
+                for idx, f in enumerate(receipts, start=1):
+                    ext = os.path.splitext(f.name)[1].lower()
+                    semantic_title = f"{proj_code} · {cat_name} · Doc {idx:02d}{ext}"
+                    Document.objects.create(
+                        expense=expense,
+                        file=f,
+                        title=semantic_title,
+                        uploaded_by=request.user
+                    )
                 
             AuditLog.objects.create(
                 user=request.user,
@@ -183,8 +193,19 @@ def expense_edit(request, pk):
             receipts = request.FILES.getlist('receipt')
             if receipts:
                 from .models import Document
-                for f in receipts:
-                    Document.objects.create(expense=exp, file=f, title=f.name, uploaded_by=request.user)
+                import os
+                cat_name = exp.category.name if exp.category else 'Evidencia'
+                proj_code = exp.project.code if exp.project else 'PROY'
+                existing_count = exp.documents.count()
+                for idx, f in enumerate(receipts, start=existing_count + 1):
+                    ext = os.path.splitext(f.name)[1].lower()
+                    semantic_title = f"{proj_code} · {cat_name} · Doc {idx:02d}{ext}"
+                    Document.objects.create(
+                        expense=exp,
+                        file=f,
+                        title=semantic_title,
+                        uploaded_by=request.user
+                    )
             
             AuditLog.objects.create(
                 user=request.user,
diff --git a/templates/expenses/expense_form.html b/templates/expenses/expense_form.html
index 4c2c42f..3475d75 100644
--- a/templates/expenses/expense_form.html
+++ b/templates/expenses/expense_form.html
@@ -99,15 +99,17 @@
                 </div>
             </div>
 
-            <div id="new-vendor-fields" style="display: none; grid-template-columns: 1fr 1fr; gap: 1.5rem; margin-bottom: 1.5rem; background: #f0fdf4; padding: 1.25rem; border-radius: 6px; border: 1px solid #bbf7d0; box-shadow: inset 0 2px 4px 0 rgba(0, 0, 0, 0.05);">
-                <div class="form-group">
-                    <label for="id_new_vendor_rut" style="font-weight: 600; font-size: 0.85rem; color: #166534;">RUT del Nuevo Proveedor</label>
+            <div id="new-vendor-fields" style="display: none; grid-template-columns: 1fr 1fr; gap: 1.5rem; margin-bottom: 1.5rem; background: #f0fdf4; padding: 1.25rem; border-radius: 6px; border: 1px solid #bbf7d0; box-shadow: inset 0 2px 4px 0 rgba(0, 0, 0, 0.05); align-items: end;">
+                <div class="form-group" style="display:flex; flex-direction:column;">
+                    <label for="id_new_vendor_rut" style="font-weight: 600; font-size: 0.85rem; color: #166534; margin-bottom: 0.35rem;">RUT del Nuevo Proveedor</label>
                     {{ form.new_vendor_rut }}
+                    <small style="color: #166534; opacity: 0.7; font-size: 0.7rem; margin-top: 0.25rem;">Ej: 12.345.678-9</small>
                     {% if form.new_vendor_rut.errors %}<div style="color: var(--efintel-danger); font-size: 0.75rem; margin-top: 4px;">{{ form.new_vendor_rut.errors }}</div>{% endif %}
                 </div>
-                <div class="form-group">
-                    <label for="id_new_vendor_name" style="font-weight: 600; font-size: 0.85rem; color: #166534;">Nombre / Razón Social del Nuevo Proveedor</label>
+                <div class="form-group" style="display:flex; flex-direction:column;">
+                    <label for="id_new_vendor_name" style="font-weight: 600; font-size: 0.85rem; color: #166534; margin-bottom: 0.35rem;">Nombre / Razón Social</label>
                     {{ form.new_vendor_name }}
+                    <small style="color: #166534; opacity: 0.7; font-size: 0.7rem; margin-top: 0.25rem;">Nombre legal del proveedor</small>
                     {% if form.new_vendor_name.errors %}<div style="color: var(--efintel-danger); font-size: 0.75rem; margin-top: 4px;">{{ form.new_vendor_name.errors }}</div>{% endif %}
                 </div>
             </div>
@@ -682,6 +684,46 @@
             }
         });
     }
+
+    // RUT Auto-formatter (XX.XXX.XXX-X)
+    const rutInput = document.getElementById('id_new_vendor_rut');
+    if (rutInput) {
+        rutInput.addEventListener('input', () => {
+            let val = rutInput.value.replace(/[^0-9kK]/g, '').toUpperCase();
+            if (val.length === 0) { rutInput.value = ''; return; }
+            
+            // Separate body and verifier digit
+            const dv = val.slice(-1);
+            let body = val.slice(0, -1);
+            
+            // Add thousands separator to body
+            body = body.replace(/\B(?=(\d{3})+(?!\d))/g, '.');
+            
+            rutInput.value = body ? `${body}-${dv}` : dv;
+        });
+
+        // Validate on blur: simple dv check using modulo 11
+        rutInput.addEventListener('blur', () => {
+            const raw = rutInput.value.replace(/\./g, '').replace(/-/g, '');
+            if (raw.length < 2) return;
+            const body = raw.slice(0, -1);
+            const dv = raw.slice(-1).toUpperCase();
+            let sum = 0, factor = 2;
+            for (let i = body.length - 1; i >= 0; i--) {
+                sum += parseInt(body[i]) * factor;
+                factor = factor === 7 ? 2 : factor + 1;
+            }
+            const remainder = 11 - (sum % 11);
+            const expectedDv = remainder === 11 ? '0' : remainder === 10 ? 'K' : String(remainder);
+            if (dv !== expectedDv) {
+                rutInput.style.border = '2px solid var(--efintel-danger)';
+                rutInput.title = `RUT inválido (dígito verificador esperado: ${expectedDv})`;
+            } else {
+                rutInput.style.border = '';
+                rutInput.title = '';
+            }
+        });
+    }
 </script>
 {% endblock %}