From 1018f1ef3706559f74dea2e783910710e9ee8f73 Mon Sep 17 00:00:00 2001
From: Lyon <88232613+pikasTech@users.noreply.github.com>
Date: Wed, 24 Jun 2026 06:47:49 +0800
Subject: [PATCH] fix(workbench): seal timing to source event time (#2025)

---
 internal/cloud/workbench-projection-writer.test.ts | 5 ++++-
 internal/cloud/workbench-projection-writer.ts      | 4 ++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/internal/cloud/workbench-projection-writer.test.ts b/internal/cloud/workbench-projection-writer.test.ts
index 23f50808..3d56938c 100644
--- a/internal/cloud/workbench-projection-writer.test.ts
+++ b/internal/cloud/workbench-projection-writer.test.ts
@@ -91,7 +91,8 @@ test("workbench projection writer commits terminal owner evidence as sealed dura
 
 test("workbench projection event commit writes trace event and checkpoint facts", async () => {
   const factWrites = [];
-  const baseStore = createCloudRuntimeStore({ now: () => "2026-06-20T11:00:00.000Z" });
+  let now = "2026-06-20T11:01:05.000Z";
+  const baseStore = createCloudRuntimeStore({ now: () => now });
   const runtimeStore = {
     allocateWorkbenchProjectedSeq(params, requestMeta) {
       return baseStore.allocateWorkbenchProjectedSeq(params, requestMeta);
@@ -106,6 +107,7 @@ test("workbench projection event commit writes trace event and checkpoint facts"
     }
   };
 
+  now = "2026-06-20T11:03:30.000Z";
   await writeWorkbenchProjectionEvent({
     runtimeStore,
     event: {
@@ -153,6 +155,7 @@ test("workbench projection event commit writes trace event and checkpoint facts"
   assert.equal(factWrites[1].params.facts.checkpoints[0].projectionStatus, "caught_up");
   assert.equal(factWrites[1].params.facts.checkpoints[0].durationMs, 90000);
   assert.equal(factWrites[1].params.facts.checkpoints[0].finishedAt, "2026-06-20T11:02:00.000Z");
+  assert.equal(factWrites[1].params.facts.checkpoints[0].lastEventAt, "2026-06-20T11:02:00.000Z");
 });
 
 test("workbench projection event writer allocates projectedSeq idempotently by source event identity", async () => {
diff --git a/internal/cloud/workbench-projection-writer.ts b/internal/cloud/workbench-projection-writer.ts
index de4046ca..dedc9e57 100644
--- a/internal/cloud/workbench-projection-writer.ts
+++ b/internal/cloud/workbench-projection-writer.ts
@@ -110,8 +110,8 @@ export async function writeWorkbenchProjectionEvent({ runtimeStore = null, event
   const previousTiming = normalizeTimingProjection(previousCheckpoint?.timing) ?? normalizeTimingProjection(previousCheckpoint);
   const explicitStartedAt = optionalTimestampValue(event.startedAt ?? event.traceStartedAt ?? event.runnerStartedAt);
   const startedAt = explicitStartedAt ?? previousTiming?.startedAt ?? (sourceSeq <= 1 ? occurredAt : null);
-  const lastEventAt = latestTimestamp(previousTiming?.lastEventAt, occurredAt, projectedAt);
-  const finishedAt = terminal ? latestTimestamp(previousTiming?.lastEventAt, optionalTimestampValue(event.finishedAt), occurredAt, projectedAt) : null;
+  const lastEventAt = latestTimestamp(previousTiming?.lastEventAt, occurredAt);
+  const finishedAt = terminal ? latestTimestamp(previousTiming?.lastEventAt, optionalTimestampValue(event.finishedAt), occurredAt) : null;
   const timing = eventTimingProjection({ startedAt, lastEventAt, finishedAt, terminal });
   const sourceEventId = workbenchSourceEventId(event, { traceId, sourceSeq, occurredAt });
   const allocation = await runtimeStore.allocateWorkbenchProjectedSeq({