diff --git a/apps/desktop/src/App.vue b/apps/desktop/src/App.vue
index 2d54582d4..1c8601304 100644
--- a/apps/desktop/src/App.vue
+++ b/apps/desktop/src/App.vue
@@ -1653,7 +1653,7 @@ async function handleQuickOpenSelect(item: any) {
 
     const schema = item.schema || item.database;
     try {
-      const result = await api.getObjectSource(item.connectionId, item.database, schema, item.objectName || item.tableName, objectType);
+      const result = await api.getObjectSource(item.connectionId, item.database, schema, item.objectName || item.tableName, objectType, item.signature);
       const tabId = queryStore.createTab(item.connectionId, item.database, `Source - ${item.objectName || item.tableName}`);
       queryStore.updateSql(tabId, result.source);
       if (item.type !== "sequence" && item.type !== "trigger" && item.type !== "type" && item.type !== "type-body") {
@@ -1661,6 +1661,7 @@ async function handleQuickOpenSelect(item: any) {
           schema,
           name: item.objectName || item.tableName,
           objectType,
+          signature: item.signature,
         });
       }
       queryStore.markTabClean(queryStore.tabs.find((tab) => tab.id === tabId));
diff --git a/apps/desktop/src/components/diff/SchemaDiffDialog.vue b/apps/desktop/src/components/diff/SchemaDiffDialog.vue
index 045362e2d..94e7a273a 100644
--- a/apps/desktop/src/components/diff/SchemaDiffDialog.vue
+++ b/apps/desktop/src/components/diff/SchemaDiffDialog.vue
@@ -527,24 +527,24 @@ async function handleSelectObject(obj: SchemaDiffObject) {
   try {
     // For "create" objects: source has it, target doesn't → fetch source DDL
     if (obj.operationType === "create" && !obj.sourceDdl) {
-      const result = await api.getObjectSource(sourceConnectionId.value, sourceDatabase.value, sourceSchema.value, obj.name, objectType);
+      const result = await api.getObjectSource(sourceConnectionId.value, sourceDatabase.value, sourceSchema.value, obj.name, objectType, obj.arguments);
       if (result?.source) obj.sourceDdl = result.source;
     }
 
     // For "delete" objects: target has it, source doesn't → fetch target DDL
     if (obj.operationType === "delete" && !obj.targetDdl) {
-      const result = await api.getObjectSource(targetConnectionId.value, targetDatabase.value, targetSchema.value, obj.name, objectType);
+      const result = await api.getObjectSource(targetConnectionId.value, targetDatabase.value, targetSchema.value, obj.name, objectType, obj.arguments);
       if (result?.source) obj.targetDdl = result.source;
     }
 
     // For "modify" objects: fetch whichever side is missing
     if (obj.operationType === "modify") {
       if (!obj.sourceDdl) {
-        const result = await api.getObjectSource(sourceConnectionId.value, sourceDatabase.value, sourceSchema.value, obj.name, objectType);
+        const result = await api.getObjectSource(sourceConnectionId.value, sourceDatabase.value, sourceSchema.value, obj.name, objectType, obj.arguments);
         if (result?.source) obj.sourceDdl = result.source;
       }
       if (!obj.targetDdl) {
-        const result = await api.getObjectSource(targetConnectionId.value, targetDatabase.value, targetSchema.value, obj.name, objectType);
+        const result = await api.getObjectSource(targetConnectionId.value, targetDatabase.value, targetSchema.value, obj.name, objectType, obj.arguments);
         if (result?.source) obj.targetDdl = result.source;
       }
     }
diff --git a/apps/desktop/src/components/objects/ObjectBrowser.vue b/apps/desktop/src/components/objects/ObjectBrowser.vue
index 6df2a7e69..9ecbaa813 100644
--- a/apps/desktop/src/components/objects/ObjectBrowser.vue
+++ b/apps/desktop/src/components/objects/ObjectBrowser.vue
@@ -1031,7 +1031,7 @@ async function openSource(row: ObjectBrowserRow) {
   const database = props.database;
   const schema = row.schema || selectedSchema.value || database;
   try {
-    const result = await api.getObjectSource(connectionId, database, schema, row.name, row.type as ObjectSourceKind);
+    const result = await api.getObjectSource(connectionId, database, schema, row.name, row.type as ObjectSourceKind, row.signature ?? undefined);
     if (sidePanelGuard.isStale(epoch)) return;
     sourceCanEdit.value = result.editable !== false && !["SEQUENCE", "TRIGGER", "TYPE", "TYPE_BODY"].includes(row.type);
     const editable = sourceCanEdit.value
@@ -1154,7 +1154,7 @@ async function confirmRename() {
   try {
     const schema = row.schema || selectedSchema.value || props.database;
     if (supportsSourceBackedRoutineRename(effectiveDatabaseType.value, row.type as ObjectSourceKind)) {
-      const source = await api.getObjectSource(props.connection.id, props.database, schema, row.name, row.type as ObjectSourceKind);
+      const source = await api.getObjectSource(props.connection.id, props.database, schema, row.name, row.type as ObjectSourceKind, row.signature ?? undefined);
       const statements = await buildRoutineRenameObjectSourceStatements({
         databaseType: effectiveDatabaseType.value,
         objectType: row.type as ObjectSourceKind,
diff --git a/apps/desktop/src/lib/__tests__/table/tableTree.spec.ts b/apps/desktop/src/lib/__tests__/table/tableTree.spec.ts
index 24f4db7c5..72d1346c0 100644
--- a/apps/desktop/src/lib/__tests__/table/tableTree.spec.ts
+++ b/apps/desktop/src/lib/__tests__/table/tableTree.spec.ts
@@ -1,5 +1,5 @@
 import { describe, expect, it } from "vitest";
-import { appendTableTreeLoadMoreNode, buildSimpleObjectTreeNodes, buildTableTreeNodes, mergeTableTreePageChildren, tablePartitionGroups, withoutTableTreeLoadMoreNodes } from "@/lib/table/tableTree";
+import { appendTableTreeLoadMoreNode, buildGroupedObjectTreeNodes, buildSimpleObjectTreeNodes, buildTableTreeNodes, mergeTableTreePageChildren, tablePartitionGroups, withoutTableTreeLoadMoreNodes } from "@/lib/table/tableTree";
 import type { ObjectInfo, TableInfo, TreeNode } from "@/types/database";
 
 const context = {
@@ -27,6 +27,24 @@ describe("PostgreSQL overloaded routines", () => {
     );
     expect(new Set(nodes.map((node) => node.id)).size).toBe(3);
   });
+
+  it("keeps grouped routine nodes distinct by identity arguments", () => {
+    const objects: ObjectInfo[] = [
+      { name: "calc", object_type: "FUNCTION", schema: "public", signature: "integer" },
+      { name: "calc", object_type: "FUNCTION", schema: "public", signature: "integer, integer" },
+      { name: "calc", object_type: "FUNCTION", schema: "public", signature: "numeric" },
+    ];
+
+    const groups = buildGroupedObjectTreeNodes({ ...context, schema: "public", objects });
+    const functionGroup = groups.find((node) => node.type === "group-functions");
+
+    expect(functionGroup?.children?.map((node) => ({ label: node.label, objectName: node.objectName, signature: node.signature }))).toEqual([
+      { label: "calc(integer)", objectName: "calc", signature: "integer" },
+      { label: "calc(integer, integer)", objectName: "calc", signature: "integer, integer" },
+      { label: "calc(numeric)", objectName: "calc", signature: "numeric" },
+    ]);
+    expect(new Set(functionGroup?.children?.map((node) => node.id) ?? []).size).toBe(3);
+  });
 });
 
 describe("programmable database objects", () => {
diff --git a/apps/desktop/src/lib/table/tableTree.ts b/apps/desktop/src/lib/table/tableTree.ts
index d45de7699..6ff3eba6c 100644
--- a/apps/desktop/src/lib/table/tableTree.ts
+++ b/apps/desktop/src/lib/table/tableTree.ts
@@ -668,7 +668,8 @@ export function buildGroupedObjectTreeNodes({ nodeId, connectionId, database, sc
     if (!name) continue;
     const t = normalizeObjectType(obj.object_type);
     const objectSchema = obj.schema ? normalizeDatabaseObjectName(obj.schema) : schema || "";
-    const key = `${t}\0${objectSchema.toLowerCase()}\0${name.toLowerCase()}`;
+    const signature = (obj.signature ?? "").trim();
+    const key = `${t}\0${objectSchema.toLowerCase()}\0${name.toLowerCase()}\0${signature.toLowerCase()}`;
     if (seen.has(key)) continue;
     seen.add(key);
     const arr = buckets.get(t) ?? [];
@@ -695,10 +696,14 @@ export function buildGroupedObjectTreeNodes({ nodeId, connectionId, database, sc
           const objectType = normalizeObjectType(obj.object_type);
           const childType = typeof def.childType === "function" ? def.childType(objectType) : def.childType;
           const objectTypeSuffix = objectType === "PACKAGE" || objectType === "PACKAGE_BODY" || objectType === "TYPE" || objectType === "TYPE_BODY" ? `:${objectType}` : "";
+          const signature = obj.signature?.trim() || "";
+          const signatureIdPart = signature && (objectType === "FUNCTION" || objectType === "PROCEDURE") ? `:${signature}` : "";
           return {
-            id: `${nodeId}:${def.key}:${childSchema ? `${childSchema}:` : ""}${obj.name}${objectTypeSuffix}`,
-            label: obj.name,
+            id: `${nodeId}:${def.key}:${childSchema ? `${childSchema}:` : ""}${obj.name}${signatureIdPart}${objectTypeSuffix}`,
+            label: signature && (objectType === "FUNCTION" || objectType === "PROCEDURE") ? `${obj.name}(${signature})` : obj.name,
             type: childType,
+            objectName: obj.name,
+            signature: signature || undefined,
             comment: obj.comment,
             valid: obj.valid ?? undefined,
             connectionId,
diff --git a/apps/desktop/src/types/database.ts b/apps/desktop/src/types/database.ts
index 7e1ddd2af..7ff217b4d 100644
--- a/apps/desktop/src/types/database.ts
+++ b/apps/desktop/src/types/database.ts
@@ -847,6 +847,7 @@ export interface QueryTab {
     schema?: string;
     name: string;
     objectType: ObjectSourceKind;
+    signature?: string;
   };
   tableMeta?: {
     schema?: string;