diff --git a/AGENTS.md b/AGENTS.md
index 44c62a4..8085053 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -1,6 +1,6 @@
 # Service Factory — ERPNext Custom App Project
 
-> **Current Version: V0.1.0025** — Each completed prompt/step increments the patch number by 1 (V0.1.0000 → V0.1.0001 → V0.1.0002…). The agent automatically commits and pushes after every step.
+> **Current Version: V0.1.0026** — Each completed prompt/step increments the patch number by 1 (V0.1.0000 → V0.1.0001 → V0.1.0002…). The agent automatically commits and pushes after every step.
 
 ## Project Overview
 
diff --git a/service_factory/service_factory/doctype/engagement_card/engagement_card.js b/service_factory/service_factory/doctype/engagement_card/engagement_card.js
index f2a5b73..ed6c37f 100644
--- a/service_factory/service_factory/doctype/engagement_card/engagement_card.js
+++ b/service_factory/service_factory/doctype/engagement_card/engagement_card.js
@@ -9,14 +9,14 @@ frappe.ui.form.on("Engagement Card", {
 		}
 		load_select_options(frm);
 		toggle_creation_fields(frm);
+		update_opportunity_state(frm);
 
-		// Filter opportunities by customer
+		// Filter opportunities by selected customer only
 		frm.set_query("opportunity", function () {
-			let filters = {};
-			if (frm.doc.customer) {
-				filters.customer = frm.doc.customer;
+			if (!frm.doc.customer) {
+				return { filters: { name: "" } };
 			}
-			return { filters: filters };
+			return { filters: { customer: frm.doc.customer } };
 		});
 	},
 	refresh: function (frm) {
@@ -26,6 +26,7 @@ frappe.ui.form.on("Engagement Card", {
 		}
 		load_select_options(frm);
 		toggle_creation_fields(frm);
+		update_opportunity_state(frm);
 
 		// Quick status actions
 		if (frm.doc.status === "Discovery" && !frm.is_new()) {
@@ -87,19 +88,32 @@ frappe.ui.form.on("Engagement Card", {
 			});
 		}
 	},
-	// Re-filter opportunities when customer changes
+	// When customer changes, clear and re-filter opportunity
 	customer: function (frm) {
 		frm._cust_user_selected = true;
+
+		// Clear opportunity if customer changed
+		if (frm.doc.opportunity) {
+			frm.set_value("opportunity", null);
+		}
+
+		// Only show opportunities linked to selected customer
 		frm.set_query("opportunity", function () {
-			let filters = {};
-			if (frm.doc.customer) {
-				filters.customer = frm.doc.customer;
+			if (!frm.doc.customer) {
+				return { filters: { name: "" } };
 			}
-			return { filters: filters };
+			return { filters: { customer: frm.doc.customer } };
 		});
+
+		update_opportunity_state(frm);
 	},
 });
 
+function update_opportunity_state(frm) {
+	// Enable opportunity only when a customer is selected
+	frm.toggle_enable("opportunity", !!frm.doc.customer);
+}
+
 function clear_customer_field(frm) {
 	if (!frm.is_new()) return;