feat(agent-ui): insert session after active tab (A6.192) (#593)

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: efecnc

packages/agent-ui/README.md

@@ -307,6 +307,7 @@ consumption of shared panel shells:
 | A6.189 | Desktop New chat uses DEFAULT_SESSION_TITLE |
 | A6.190 | Deleted session id blocklist ops |
 | A6.191 | Hydrate active session resolve |
+| A6.192 | Insert session after active tab |
 
 ### A5 complete enough
 

packages/agent-ui/src/__tests__/insertSessionAfterActive.test.ts

@@ -0,0 +1,20 @@
+import { describe, expect, it } from "vitest";
+import { insertSessionAfterActive } from "../lib/insertSessionAfterActive.js";
+
+describe("insertSessionAfterActive", () => {
+  it("inserts after active", () => {
+    expect(
+      insertSessionAfterActive(
+        [{ id: "a" }, { id: "b" }],
+        "a",
+        { id: "n" },
+      ),
+    ).toEqual([{ id: "a" }, { id: "n" }, { id: "b" }]);
+  });
+  it("appends when missing active", () => {
+    expect(insertSessionAfterActive([{ id: "a" }], "z", { id: "n" })).toEqual([
+      { id: "a" },
+      { id: "n" },
+    ]);
+  });
+});

packages/agent-ui/src/index.ts

@@ -892,6 +892,7 @@ export {
   resolveActiveSessionOnHydrate,
   createUntitledSessionMeta,
 } from "./lib/resolveActiveSessionOnHydrate.js";
+export { insertSessionAfterActive } from "./lib/insertSessionAfterActive.js";
 export type { SessionIdTitle } from "./lib/resolveActiveSessionOnHydrate.js";
 export type {
   UntitledSessionMeta,

packages/agent-ui/src/lib/insertSessionAfterActive.ts

@@ -0,0 +1,20 @@
+/**
+ * Pure session-list insert after the active tab (A6.192).
+ */
+
+/** Insert `meta` immediately after the active session (or append). */
+export function insertSessionAfterActive<T extends { id: string }>(
+  sessions: readonly T[],
+  activeId: string | null | undefined,
+  meta: T,
+): T[] {
+  const activeIdx = activeId
+    ? sessions.findIndex((s) => s.id === activeId)
+    : -1;
+  if (activeIdx === -1) return [...sessions, meta];
+  return [
+    ...sessions.slice(0, activeIdx + 1),
+    meta,
+    ...sessions.slice(activeIdx + 1),
+  ];
+}

src/modules/ai/store/chatStore.ts

@@ -4,6 +4,7 @@ import {
   appendDeletedSessionId,
   resolveActiveSessionOnHydrate,
   createUntitledSessionMeta,
+  insertSessionAfterActive,
 } from "@altai/agent-ui";
 import type { UIMessage } from "ai";
 import { native } from "../lib/native";
@@ -900,17 +901,11 @@ export const useChatStore = create<StoreState>((set, get) => ({
       updatedAt: Date.now(),
     };
     const current = get().sessions;
-    const activeIdx = current.findIndex(
-      (s) => s.id === get().activeSessionId,
+    const next = insertSessionAfterActive(
+      current,
+      get().activeSessionId,
+      meta,
     );
-    const next =
-      activeIdx === -1
-        ? [...current, meta]
-        : [
-            ...current.slice(0, activeIdx + 1),
-            meta,
-            ...current.slice(activeIdx + 1),
-          ];
     set({
       sessions: next,
       activeSessionId: id,