fix(web): Lineage keeps the latest batch of finished agents in view

apps/web/src/components/chat/ThreadRelationshipsControl.browser.test.tsx

@@ -210,6 +210,60 @@ it("opens an idle child from Lineage when its shell has not been loaded", async
   );
 });
 
+it("keeps the latest batch of finished agents in view after a later turn launches none", async () => {
+  setup();
+  const projection = makeThreadProjectionFixture();
+  const agent = (id: string, runId: string, title: string) => ({
+    id: NodeId.make(id),
+    threadId: projection.thread.id,
+    runId,
+    parentNodeId: NodeId.make("parent"),
+    origin: "provider_native",
+    createdBy: "agent",
+    driver: "claudeAgent",
+    providerInstanceId: projection.thread.providerInstanceId,
+    providerThreadId: null,
+    childThreadId: ThreadId.make(`${id}-thread`),
+    nativeTaskRef: null,
+    prompt: title,
+    title,
+    model: null,
+    status: "completed",
+    result: null,
+    startedAt: projection.thread.updatedAt,
+    completedAt: projection.thread.updatedAt,
+    updatedAt: projection.thread.updatedAt,
+  });
+  state.projection = {
+    ...projection,
+    runs: [1, 2, 3].map((ordinal) => ({
+      id: `run-${ordinal}`,
+      ordinal,
+      status: "completed",
+      startedAt: projection.thread.updatedAt,
+    })),
+    subagents: [
+      agent("older", "run-1", "Older batch agent"),
+      agent("latest", "run-2", "Latest batch agent"),
+    ],
+  };
+  await using screen = await render(
+    <ThreadRelationshipsPanel
+      environmentId={EnvironmentId.make("local")}
+      threadId={projection.thread.id}
+      showLineage
+      showSideChats
+    />,
+  );
+
+  await expect
+    .element(screen.getByRole("button", { name: /Latest batch agent/ }))
+    .toBeInTheDocument();
+  await expect
+    .element(screen.getByRole("button", { name: /Older batch agent/ }))
+    .not.toBeInTheDocument();
+});
+
 it("shows a lineage thread's full title in its tooltip", async () => {
   setup();
   const longTitle = "Compare the lineage tooltip against a title that the row truncates";

apps/web/src/components/chat/ThreadRelationshipsControl.tsx

@@ -37,6 +37,7 @@ import {
   type OrchestrationV2RemoteTaskChild,
   type OrchestrationV2Subagent,
   type OrchestrationV2ThreadShell,
+  type RunId,
   type ServerProvider,
   type ThreadId,
 } from "@t3tools/contracts";
@@ -541,6 +542,23 @@ export function ThreadRelationshipsPanel(props: {
       Object.hasOwn(resolvedThreadTitles, threadId),
   );
   const canDetach = projection ? canDetachThreadProviderSession(projection) : false;
+  // The latest batch stays in view after it finishes, until a later turn launches agents.
+  const runOrdinals = new Map(
+    (projection?.runs ?? [])
+      .filter((run) => run.status !== "rolled_back")
+      .map((run) => [run.id, run.ordinal]),
+  );
+  const latestBatchRunId = projected.reduce<RunId | null>(
+    (latest, agent) =>
+      agent.runId !== null &&
+      runOrdinals.has(agent.runId) &&
+      (latest === null || runOrdinals.get(agent.runId)! > runOrdinals.get(latest)!)
+        ? agent.runId
+        : latest,
+    null,
+  );
+  const isPreviousAgent = (status: string | null | undefined, runId: RunId | null | undefined) =>
+    isFinishedAgentStatus(status) && (latestBatchRunId === null || runId !== latestBatchRunId);
 
   const {
     related = [],
@@ -552,13 +570,16 @@ export function ThreadRelationshipsPanel(props: {
     if (!isParent && graph.nodes.get(threadId)?.thread?.lineage.sideChat === true)
       return "sideChats";
     if (edge.kind !== "subagent" || isParent) return "related";
-    return isFinishedAgentStatus(edge.status) ? "previous" : "active";
+    return isPreviousAgent(edge.status, subagentsByThreadId.get(threadId)?.runId)
+      ? "previous"
+      : "active";
   });
   const { remoteActive = [], remotePrevious = [] } = groupBy(
     (projection?.subagents ?? [])
       .filter((agent): agent is RemoteSubagent => agent.remoteChild !== undefined)
       .map((remote) => ({ remote })),
-    ({ remote }) => (isFinishedAgentStatus(remote.status) ? "remotePrevious" : "remoteActive"),
+    ({ remote }) =>
+      isPreviousAgent(remote.status, remote.runId) ? "remotePrevious" : "remoteActive",
   );
   const groups: ReadonlyArray<{
     id: string;