diff --git a/pos/blueprints/service_order_bp.py b/pos/blueprints/service_order_bp.py
index df7687f..85dc91d 100644
--- a/pos/blueprints/service_order_bp.py
+++ b/pos/blueprints/service_order_bp.py
@@ -356,6 +356,60 @@ def assign_mechanic_endpoint(so_id):
         conn.close()
 
 
+@service_order_bp.route('/inventory-search', methods=['GET'])
+@require_auth('workshop.view')
+def inventory_search():
+    """Search active inventory for attaching parts to a service order.
+
+    Does not require inventory.view so workshop users can pick parts.
+    """
+    q = request.args.get('q', '').strip()
+    if not q:
+        return jsonify({'data': []})
+
+    branch_id = request.args.get('branch_id', g.branch_id)
+    conn = get_tenant_conn(g.tenant_id)
+    try:
+        cur = conn.cursor()
+        like = f'%{q}%'
+        if branch_id:
+            cur.execute("""
+                SELECT i.id, i.part_number, i.name, i.brand, i.unit,
+                       COALESCE((SELECT stock FROM inventory_stock
+                                 WHERE inventory_id = i.id AND branch_id = %s), 0) AS stock,
+                       i.cost, i.price_1
+                FROM inventory i
+                WHERE i.is_active = true
+                  AND (i.part_number ILIKE %s OR i.name ILIKE %s OR i.barcode ILIKE %s)
+                ORDER BY i.name
+                LIMIT 20
+            """, (branch_id, like, like, like))
+        else:
+            cur.execute("""
+                SELECT i.id, i.part_number, i.name, i.brand, i.unit,
+                       COALESCE((SELECT stock FROM inventory_stock_summary
+                                 WHERE inventory_id = i.id), 0) AS stock,
+                       i.cost, i.price_1
+                FROM inventory i
+                WHERE i.is_active = true
+                  AND (i.part_number ILIKE %s OR i.name ILIKE %s OR i.barcode ILIKE %s)
+                ORDER BY i.name
+                LIMIT 20
+            """, (like, like, like))
+        items = []
+        for r in cur.fetchall():
+            items.append({
+                'id': r[0], 'part_number': r[1], 'name': r[2], 'brand': r[3], 'unit': r[4],
+                'stock': float(r[5]) if r[5] else 0,
+                'cost': float(r[6]) if r[6] else 0,
+                'price_1': float(r[7]) if r[7] else 0,
+            })
+        cur.close()
+        return jsonify({'data': items})
+    finally:
+        conn.close()
+
+
 # ─── Service catalog (reusable labor) ─────────────
 
 
diff --git a/pos/services/service_order_engine.py b/pos/services/service_order_engine.py
index 5c96389..ffb55e8 100644
--- a/pos/services/service_order_engine.py
+++ b/pos/services/service_order_engine.py
@@ -13,7 +13,7 @@ VALID_TRANSITIONS = {
     'diagnosis': ['waiting_parts', 'repair', 'cancelled'],
     'waiting_parts': ['repair', 'cancelled'],
     'repair': ['quality_check', 'cancelled'],
-    'quality_check': ['ready', 'repair', 'cancelled'],
+    'quality_check': ['ready', 'cancelled'],
     'ready': ['delivered', 'cancelled'],
     'delivered': [],
     'cancelled': [],
diff --git a/pos/static/js/workshop.js b/pos/static/js/workshop.js
index 55a0816..4da383a 100644
--- a/pos/static/js/workshop.js
+++ b/pos/static/js/workshop.js
@@ -16,6 +16,8 @@ var Workshop = (function() {
     var branches = [];
     var currentOrderId = null;
     var currentOrder = null;
+    var selectedInventoryItem = null;
+    var itemSearchTimer = null;
     var currentView = 'list';
     var currentPage = 1;
     var perPage = 25;
@@ -48,6 +50,17 @@ var Workshop = (function() {
         cancelled: 'Cancelado'
     };
 
+    var VALID_NEXT = {
+        received: ['diagnosis', 'cancelled'],
+        diagnosis: ['waiting_parts', 'repair', 'cancelled'],
+        waiting_parts: ['repair', 'cancelled'],
+        repair: ['quality_check', 'cancelled'],
+        quality_check: ['ready', 'cancelled'],
+        ready: ['delivered', 'cancelled'],
+        delivered: [],
+        cancelled: []
+    };
+
     var DELIVERY_LABELS = {
         pickup: 'Pasa cliente',
         delivery: 'Envío a domicilio',
@@ -362,8 +375,18 @@ var Workshop = (function() {
 
             '<div class="so-tab-panel" id="tab-service" ' + (selectedTab === 'service' ? '' : 'style="display:none;"') + '>' +
             '  <div class="so-detail__section">' +
-            '    <h3>Observaciones</h3>' +
-            '    <p>' + esc(o.reception_notes || 'Sin observaciones') + '</p>' +
+            '    <h3>Notas</h3>' +
+            '    <div class="so-notes-grid">' +
+            '      <label class="form-label">Recepción</label>' +
+            '      <textarea id="noteReception" class="form-input" rows="2" ' + (canEdit ? '' : 'readonly') + '>' + esc(o.reception_notes || '') + '</textarea>' +
+            '      <label class="form-label">Diagnóstico</label>' +
+            '      <textarea id="noteDiagnosis" class="form-input" rows="2" ' + (canEdit ? '' : 'readonly') + '>' + esc(o.diagnosis_notes || '') + '</textarea>' +
+            '      <label class="form-label">Reparación</label>' +
+            '      <textarea id="noteRepair" class="form-input" rows="2" ' + (canEdit ? '' : 'readonly') + '>' + esc(o.repair_notes || '') + '</textarea>' +
+            '      <label class="form-label">Entrega</label>' +
+            '      <textarea id="noteDelivery" class="form-input" rows="2" ' + (canEdit ? '' : 'readonly') + '>' + esc(o.delivery_notes || '') + '</textarea>' +
+            '    </div>' +
+            (canEdit ? '    <button class="btn btn--secondary" style="margin-top:var(--space-2);" onclick="Workshop.saveNotes()">Guardar notas</button>' : '') +
             '  </div>' +
             '  <div class="so-detail__section">' +
             '    <h3>Bitácora</h3>' +
@@ -379,10 +402,12 @@ var Workshop = (function() {
 
         // Footer actions
         var footer = document.getElementById('detailFooter');
-        var statusHtml = canEdit ?
+        var allowedNext = VALID_NEXT[o.status] || [];
+        var statusHtml = canEdit && allowedNext.length ?
             '<div class="so-detail__actions" style="margin-right:auto;">' +
             '  <select class="form-input" id="statusSelect" style="width:auto;">' +
-            COLUMNS.map(function(c) { return '<option value="' + c.key + '"' + (c.key === o.status ? ' selected' : '') + '>' + c.label + '</option>'; }).join('') +
+            '<option value="' + esc(o.status) + '" selected>' + esc(STATUS_LABELS[o.status] || o.status) + '</option>' +
+            allowedNext.map(function(s) { return '<option value="' + s + '">' + esc(STATUS_LABELS[s] || s) + '</option>'; }).join('') +
             '  </select>' +
             '  <button class="btn btn--primary" onclick="Workshop.changeStatus()">Actualizar estado</button>' +
             '</div>' : '';
@@ -442,9 +467,13 @@ var Workshop = (function() {
         var laborHeader = '<tr><th>Concepto</th><th>Horas</th>' + (hidePrices ? '' : '<th>Precio/hr</th><th>Total</th>') + '<th>Estado</th></tr>';
 
         var addParts = canEdit ?
-            '<div style="margin-top:var(--space-3);display:flex;gap:var(--space-2);">' +
-            '  <input class="form-input" id="newItemSearch" placeholder="Buscar refacción por nombre/número" style="flex:1;" />' +
-            '  <button class="btn btn--secondary" onclick="Workshop.addItemPlaceholder()">Agregar</button>' +
+            '<div style="margin-top:var(--space-3);display:flex;gap:var(--space-2);align-items:flex-start;flex-wrap:wrap;">' +
+            '  <div style="position:relative;flex:1;min-width:200px;">' +
+            '    <input class="form-input" id="newItemSearch" placeholder="Buscar refacción por nombre/número" autocomplete="off" oninput="Workshop.searchItemsForSO()" />' +
+            '    <div id="itemSearchResults" style="display:none;position:absolute;z-index:10;top:100%;left:0;right:0;max-height:220px;overflow-y:auto;background:#fff;border:1px solid var(--color-border);border-radius:var(--radius-md);box-shadow:0 4px 12px rgba(0,0,0,.15);"></div>' +
+            '  </div>' +
+            '  <input class="form-input" id="newItemQty" type="number" value="1" min="1" style="width:80px;" />' +
+            '  <button class="btn btn--secondary" onclick="Workshop.addSelectedItem()">Agregar</button>' +
             '</div>' : '';
 
         var addLabor = canEdit ?
@@ -502,6 +531,10 @@ var Workshop = (function() {
     function changeStatus() {
         if (!currentOrderId) return;
         var newStatus = document.getElementById('statusSelect').value;
+        if (currentOrder && newStatus === currentOrder.status) {
+            alert('Selecciona un estado diferente al actual');
+            return;
+        }
         api('PUT', '/' + currentOrderId + '/status', {status: newStatus})
             .then(function() {
                 closeDetailModal();
@@ -511,6 +544,27 @@ var Workshop = (function() {
             .catch(function(e) { alert('Error: ' + e.message); });
     }
 
+    function saveNotes() {
+        if (!currentOrderId) return;
+        var payload = {
+            reception_notes: document.getElementById('noteReception').value,
+            diagnosis_notes: document.getElementById('noteDiagnosis').value,
+            repair_notes: document.getElementById('noteRepair').value,
+            delivery_notes: document.getElementById('noteDelivery').value
+        };
+        api('PUT', '/' + currentOrderId, payload)
+            .then(function() {
+                alert('Notas guardadas');
+                if (currentOrder) {
+                    currentOrder.reception_notes = payload.reception_notes;
+                    currentOrder.diagnosis_notes = payload.diagnosis_notes;
+                    currentOrder.repair_notes = payload.repair_notes;
+                    currentOrder.delivery_notes = payload.delivery_notes;
+                }
+            })
+            .catch(function(e) { alert('Error: ' + e.message); });
+    }
+
     function reserveItem(itemId) {
         api('POST', '/' + currentOrderId + '/items/' + itemId + '/reserve', {})
             .then(function() {
@@ -521,15 +575,94 @@ var Workshop = (function() {
             .catch(function(e) { alert('Error: ' + e.message); });
     }
 
-    function addItemPlaceholder() {
+    function hideItemSearchResults() {
+        var box = document.getElementById('itemSearchResults');
+        if (box) box.style.display = 'none';
+    }
+
+    function searchItemsForSO() {
+        var input = document.getElementById('newItemSearch');
+        var box = document.getElementById('itemSearchResults');
+        var q = input.value.trim();
+        selectedInventoryItem = null;
+        if (!q || q.length < 2) {
+            box.style.display = 'none';
+            box.innerHTML = '';
+            return;
+        }
+        clearTimeout(itemSearchTimer);
+        itemSearchTimer = setTimeout(function() {
+            var branchId = currentOrder && currentOrder.branch_id ? currentOrder.branch_id : '';
+            fetch('/pos/api/service-orders/inventory-search?q=' + encodeURIComponent(q) + '&branch_id=' + encodeURIComponent(branchId), {headers: headers()})
+                .then(function(r) { return r.json(); })
+                .then(function(d) {
+                    var items = d.data || [];
+                    if (!items.length) {
+                        box.innerHTML = '<div style="padding:var(--space-2);color:var(--color-text-muted);">Sin resultados</div>';
+                        box.style.display = 'block';
+                        return;
+                    }
+                    box.innerHTML = items.map(function(it) {
+                        return '<div class="so-search-result" data-id="' + it.id + '" data-name="' + esc(it.name) + '" data-part="' + esc(it.part_number || '') + '" data-price="' + (it.price_1 || 0) + '" data-cost="' + (it.cost || 0) + '" style="padding:var(--space-2);cursor:pointer;border-bottom:1px solid var(--color-border);" onclick="Workshop.selectInventoryItem(' + it.id + ')">' +
+                            '<div><strong>' + esc(it.name) + '</strong></div>' +
+                            '<small>' + esc(it.part_number || '') + ' · ' + esc(it.brand || '') + ' · Stock: ' + fmt(it.stock) + (hidePrices ? '' : ' · ' + fmtMoney(it.price_1)) + '</small>' +
+                            '</div>';
+                    }).join('');
+                    box.style.display = 'block';
+                })
+                .catch(function() {
+                    box.style.display = 'none';
+                });
+        }, 250);
+    }
+
+    function selectInventoryItem(id) {
+        var box = document.getElementById('itemSearchResults');
+        var div = box.querySelector('[data-id="' + id + '"]');
+        if (!div) return;
+        selectedInventoryItem = {
+            id: id,
+            name: div.dataset.name || '',
+            part_number: div.dataset.part || '',
+            unit_price: parseFloat(div.dataset.price) || 0,
+            unit_cost: parseFloat(div.dataset.cost) || 0
+        };
+        document.getElementById('newItemSearch').value = selectedInventoryItem.name;
+        box.style.display = 'none';
+    }
+
+    function addSelectedItem() {
+        if (!currentOrderId) return;
+        var qty = parseInt(document.getElementById('newItemQty').value, 10) || 1;
+        if (selectedInventoryItem) {
+            api('POST', '/' + currentOrderId + '/items', {
+                inventory_id: selectedInventoryItem.id,
+                part_number: selectedInventoryItem.part_number,
+                name: selectedInventoryItem.name,
+                quantity: qty,
+                unit_cost: selectedInventoryItem.unit_cost,
+                unit_price: selectedInventoryItem.unit_price,
+                status: 'pending'
+            }).then(function() {
+                selectedInventoryItem = null;
+                document.getElementById('newItemSearch').value = '';
+                document.getElementById('newItemQty').value = '1';
+                openDetail(currentOrderId);
+            }).catch(function(e) { alert('Error: ' + e.message); });
+            return;
+        }
+        // Fallback: manual placeholder (no inventory link)
         var name = document.getElementById('newItemSearch').value.trim();
         if (!name) return;
+        if (!confirm('No seleccionaste una refacción del inventario. ¿Agregar como concepto manual? No podrá reservarse.')) return;
         api('POST', '/' + currentOrderId + '/items', {
             name: name,
-            quantity: 1,
+            quantity: qty,
             unit_price: 0,
             status: 'pending'
         }).then(function() {
+            document.getElementById('newItemSearch').value = '';
+            document.getElementById('newItemQty').value = '1';
             openDetail(currentOrderId);
         }).catch(function(e) { alert('Error: ' + e.message); });
     }
@@ -768,7 +901,10 @@ var Workshop = (function() {
         switchTab: switchTab,
         changeStatus: changeStatus,
         reserveItem: reserveItem,
-        addItemPlaceholder: addItemPlaceholder,
+        saveNotes: saveNotes,
+        searchItemsForSO: searchItemsForSO,
+        selectInventoryItem: selectInventoryItem,
+        addSelectedItem: addSelectedItem,
         addLabor: addLabor,
         convertToSale: convertToSale,
         printOrder: printOrder,
diff --git a/pos/templates/workshop.html b/pos/templates/workshop.html
index 3f208a8..3234038 100644
--- a/pos/templates/workshop.html
+++ b/pos/templates/workshop.html
@@ -15,7 +15,12 @@
   <meta name="theme-color" content="#F5A623" />
   <link rel="shortcut icon" type="image/png" href="/pos/static/pwa/icon-192.png" />
 
-  <link rel="stylesheet" href="/pos/static/css/workshop.css?v=33">
+  <link rel="stylesheet" href="/pos/static/css/workshop.css?v=34">
+  <style>
+    .so-notes-grid { display: grid; grid-template-columns: 120px 1fr; gap: var(--space-2); align-items: start; }
+    .so-notes-grid .form-label { margin: 0; padding-top: var(--space-2); }
+    .so-search-result:hover { background: var(--color-bg-secondary); }
+  </style>
 </head>
 <body>
 
@@ -295,7 +300,7 @@
 <script src="/pos/static/js/pos-utils.js?v=33" defer></script>
 <script src="/pos/static/js/sidebar.js?v=33" defer></script>
 <script src="/pos/static/js/offline-banner.js" defer></script>
-<script src="/pos/static/js/workshop.js?v=33" defer></script>
+<script src="/pos/static/js/workshop.js?v=34" defer></script>
 <script>if('serviceWorker' in navigator){navigator.serviceWorker.register('/pos/sw.js',{scope:'/pos/'});}</script>
 <script src="/pos/static/js/pwa-install.js" defer></script>
 <script src="/pos/static/js/chat.js" defer></script>