fix: derive Workbench rail titles from Kafka index

internal/cloud/kafka-event-bridge.ts

@@ -416,6 +416,14 @@ function startLiveHwlabKafkaEventBridge({ config, env = process.env, logger = co
         }
       };
     },
+    workbenchSessionSummaries() {
+      return sessionIndex?.sessionSummaries() ?? {
+        ok: false,
+        sessions: [],
+        warning: { code: "workbench_kafka_session_index_disabled", message: "Session summary index is disabled.", blocking: false, valuesRedacted: true },
+        valuesRedacted: true
+      };
+    },
     liveSubscriberCount() { return subscribers.size; },
     valuesPrinted: false
   };
@@ -487,6 +495,14 @@ function combineKafkaEventBridgeComponents(config, components) {
       if (typeof liveOwner?.queryHwlabEventRetention !== "function") throw contractError("hwlab_kafka_refresh_query_unconfigured", "Kafka refresh retention query is not configured.");
       return liveOwner.queryHwlabEventRetention(params);
     },
+    workbenchSessionSummaries() {
+      return liveOwner?.workbenchSessionSummaries?.() ?? {
+        ok: false,
+        sessions: [],
+        warning: { code: "workbench_kafka_session_index_disabled", message: "Session summary index is disabled.", blocking: false, valuesRedacted: true },
+        valuesRedacted: true
+      };
+    },
     liveSubscriberCount() {
       const owner = components.find((component) => typeof component.liveSubscriberCount === "function");
       return owner?.liveSubscriberCount() ?? 0;

internal/cloud/workbench-kafka-session-index.test.ts

@@ -36,6 +36,9 @@ test("process session index bootstraps once and serves repeated scoped queries f
   assert.equal(first.result.index.hit, true);
   assert.equal(first.result.index.indexedEventCount, 3);
   assert.equal(queryCount, 1);
+  assert.deepEqual(index.sessionSummaries().sessions, [
+    { sessionId: "ses_a", firstUserMessagePreview: "prompt ses_a", lastUserMessageAt: "2026-07-20T00:00:01.000Z", valuesRedacted: true }
+  ]);
 
   index.observeLive(envelope("ses_a", "trc_a", 4), { topic: "hwlab.event.v1", partition: 0, offset: "3" });
   const live = index.query({ sessionId: "ses_a", limit: 10 });
@@ -106,6 +109,7 @@ function envelope(sessionId: string, traceId: string, seq: number) {
     traceId,
     event: {
       type: seq === 1 ? "user" : "assistant",
+      text: seq === 1 ? `prompt ${sessionId}` : "reply",
       sessionId,
       traceId,
       createdAt: `2026-07-20T00:00:0${seq}.000Z`

internal/cloud/workbench-kafka-session-index.ts

@@ -227,6 +227,34 @@ export function createWorkbenchKafkaSessionIndex(options = {}) {
     };
   }
 
+  function sessionSummaries() {
+    if (!ready || !state.globalComplete) {
+      const reason = !ready ? "index-not-ready" : "global-capacity-exceeded";
+      return {
+        ok: false,
+        sessions: [],
+        warning: warning("workbench_kafka_session_summary_unavailable", `Session summary index is unavailable (${reason}).`),
+        status: status(),
+        valuesRedacted: true
+      };
+    }
+    const sessions = [];
+    for (const [id, records] of state.bySession.entries()) {
+      if (state.incompleteSessions.has(id)) continue;
+      const userEvents = records.map((record) => record.value?.event).filter((event) => firstText(event?.type, event?.eventType) === "user");
+      const firstPreview = firstText(userEvents[0]?.text, userEvents[0]?.message);
+      if (!firstPreview) continue;
+      const lastUserEvent = userEvents.at(-1);
+      sessions.push({
+        sessionId: id,
+        firstUserMessagePreview: firstPreview.slice(0, 240),
+        lastUserMessageAt: firstText(lastUserEvent?.createdAt, lastUserEvent?.submittedAt),
+        valuesRedacted: true
+      });
+    }
+    return { ok: true, sessions, warning: null, status: status(), valuesRedacted: true };
+  }
+
   function emptyState() {
     return {
       records: [],
@@ -295,6 +323,7 @@ export function createWorkbenchKafkaSessionIndex(options = {}) {
     stop,
     observeLive,
     query,
+    sessionSummaries,
     status,
     rebuild,
     valuesPrinted: false

internal/workbench/http.ts

@@ -73,14 +73,26 @@ function requireAuthorization(request: Request, options: { snapshot?: unknown; a
   if (!expected || actual !== expected) throw Object.assign(new Error("Workbench API internal authentication failed"), { code: "auth_required" });
 }
 
-async function nativeSessionList(options: { snapshot?: () => Promise<any>; mode?: WorkbenchMode }, url: URL) {
+async function nativeSessionList(options: { snapshot?: () => Promise<any>; mode?: WorkbenchMode; kafkaEventBridge?: any }, url: URL) {
   const state = await requiredSnapshot(options);
   const owner = text(url.searchParams.get("ownerUserId"));
+  const kafkaSummary = options.mode === "agentrun-native" ? options.kafkaEventBridge?.workbenchSessionSummaries?.() : null;
+  const kafkaSummaryBySession = new Map((Array.isArray(kafkaSummary?.sessions) ? kafkaSummary.sessions : []).map((session: any) => [text(session.sessionId), session]));
   const sessions = Object.values(state.sessions)
     .filter((session: any) => !owner || session.ownerUserId === owner)
-    .map((session: any) => ({ ...session, firstUserMessagePreview: firstUserMessagePreview(session.messages) ?? (text(session.firstUserMessagePreview) || null) }))
+    .map((session: any) => {
+      const summary = kafkaSummaryBySession.get(text(session.sessionId)) as any;
+      const nativeTestPreview = options.mode === "agentrun-native" ? null : firstUserMessagePreview(session.messages) ?? (text(session.firstUserMessagePreview) || null);
+      return {
+        ...session,
+        firstUserMessagePreview: text(summary?.firstUserMessagePreview) || nativeTestPreview,
+        lastUserMessageAt: text(summary?.lastUserMessageAt) || null,
+        updatedAt: text(summary?.lastUserMessageAt) || session.updatedAt
+      };
+    })
     .sort((left: any, right: any) => String(right.updatedAt).localeCompare(String(left.updatedAt)));
-  return json(200, { ok: true, status: "ready", sessions, count: sessions.length, mode: options.mode ?? "native-test" });
+  const warnings = kafkaSummary?.warning ? [kafkaSummary.warning] : [];
+  return json(200, { ok: true, status: "ready", sessions, count: sessions.length, warnings, mode: options.mode ?? "native-test" });
 }
 async function nativeSessionDetail(options: { snapshot?: () => Promise<any>; mode?: WorkbenchMode }, sessionId: string, messagesOnly: boolean) {
   const state = await requiredSnapshot(options);

internal/workbench/workbench.test.ts

@@ -103,6 +103,35 @@ describe("Workbench native HTTP adapter", () => {
     });
   });
 
+  test("AgentRun native session list uses Kafka index summaries instead of admission messages", async () => {
+    const app = createWorkbenchHttpApp({
+      mode: "agentrun-native",
+      kafkaEventBridge: {
+        workbenchSessionSummaries() {
+          return { ok: true, sessions: [{ sessionId: "ses_title", firstUserMessagePreview: "Kafka title", lastUserMessageAt: "2026-07-20T01:00:00.000Z" }] };
+        }
+      },
+      async dispatch() { return { ok: true }; },
+      async snapshot() {
+        return {
+          sessions: {
+            ses_title: {
+              sessionId: "ses_title",
+              updatedAt: "2026-07-20T00:00:00.000Z",
+              messages: [{ role: "user", content: "admission snapshot title" }]
+            }
+          },
+          turns: {}
+        };
+      }
+    });
+
+    const response = await app.fetch(new Request("http://native.test/v1/workbench/sessions"));
+    expect(await response.json()).toMatchObject({
+      sessions: [{ sessionId: "ses_title", firstUserMessagePreview: "Kafka title", lastUserMessageAt: "2026-07-20T01:00:00.000Z" }]
+    });
+  });
+
   test("authorizes only the Workbench navigation entry", async () => {
     const app = createWorkbenchHttpApp({
       async dispatch() { return { ok: true }; },

web/hwlab-cloud-web/src/stores/workbench-message-projection-runtime.test.ts

@@ -151,6 +151,8 @@ test("workbench active state uses Kafka SSE without HTTP session or terminal pro
   assert.doesNotMatch(source, /fetchSessionDetailPage|fetchSessionMessagesPage/u);
   assert.doesNotMatch(loadBlock, /fetchSession\(|fetchSessionMessages\(/u);
   assert.match(loadBlock, /workbenchSessionNavigationSeed\(id/u);
+  assert.match(source, /firstUserMessagePreview: firstNonEmptyString\(source\?\.firstUserMessagePreview\)/u);
+  assert.match(source, /lastUserMessageAt: firstNonEmptyString\(source\?\.lastUserMessageAt\)/u);
   assert.doesNotMatch(submitBlock, /applyTurnStatusSnapshot|completeTrace/u);
   assert.doesNotMatch(traceDetailApplyBlock, /rememberTurnStatus|projectTurnAuthorityToMessages|chatPending\.value\s*=\s*false/u);
   assert.doesNotMatch(source, /sealRestoredActiveTurnMessages|messageNeedsRestoredTurnSeal|refreshSessionStatusAuthority|readTerminalTraceDetailGaps/u);

web/hwlab-cloud-web/src/stores/workbench.ts

@@ -1424,6 +1424,9 @@ function workbenchSessionNavigationSeed(sessionId: string, source: WorkbenchSess
   return {
     sessionId,
     threadId: firstNonEmptyString(source?.threadId),
+    firstUserMessagePreview: firstNonEmptyString(source?.firstUserMessagePreview),
+    lastUserMessageAt: firstNonEmptyString(source?.lastUserMessageAt),
+    updatedAt: firstNonEmptyString(source?.lastUserMessageAt, source?.updatedAt),
     messages: [],
     messageCount: 0
   };