From ad70a508a879b826cc546562e16c4f43df7282a3 Mon Sep 17 00:00:00 2001
From: lyon <liang6516@outlook.com>
Date: Fri, 19 Jun 2026 12:43:16 +0800
Subject: [PATCH] fix: cache terminal durable workbench trace reads

---
 internal/cloud/server-workbench-http.test.ts |  3 ++
 internal/cloud/workbench-facts-store.ts      | 34 +++++++++++++++++---
 2 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/internal/cloud/server-workbench-http.test.ts b/internal/cloud/server-workbench-http.test.ts
index c771cd1c..3588037d 100644
--- a/internal/cloud/server-workbench-http.test.ts
+++ b/internal/cloud/server-workbench-http.test.ts
@@ -183,8 +183,10 @@ test("workbench read model recovers trace events from durable projection without
     async ensureBootstrap() {},
     async authenticate() { return { ok: true, actor: ACTOR, session: { id: "uss_workbench_reader" } }; }
   };
+  let traceQueryCount = 0;
   const runtimeStore = {
     async queryAgentTraceEvents(params = {}) {
+      traceQueryCount += 1;
       assert.equal(params.traceId, traceId);
       return { events: durableEvents, count: durableEvents.length };
     }
@@ -210,6 +212,7 @@ test("workbench read model recovers trace events from durable projection without
     assert.equal(trace.body.events.length, 2);
     assert.equal(trace.body.traceStatus, "completed");
     assert.equal(trace.body.hasMore, false);
+    assert.equal(traceQueryCount, 1);
   } finally {
     await new Promise((resolve, reject) => server.close((error) => error ? reject(error) : resolve()));
   }
diff --git a/internal/cloud/workbench-facts-store.ts b/internal/cloud/workbench-facts-store.ts
index 27451569..9f04a07a 100644
--- a/internal/cloud/workbench-facts-store.ts
+++ b/internal/cloud/workbench-facts-store.ts
@@ -6,6 +6,9 @@ import { defaultCodeAgentTraceStore } from "./code-agent-trace-store.ts";
 import { safeConversationId, safeSessionId, safeTraceId } from "./server-http-utils.ts";
 import { durableTraceStatus, normalizeWorkbenchStatus, TERMINAL_STATUSES, traceTerminalEvidence } from "./workbench-turn-projection.ts";
 
+const TERMINAL_DURABLE_TRACE_CACHE_MAX = 256;
+const terminalDurableTraceCache = new Map();
+
 export function createWorkbenchFactsStore(options = {}, actor = null) {
   const accessStore = options.accessController?.store ?? options.accessController ?? null;
   const traceStore = options.traceStore ?? defaultCodeAgentTraceStore;
@@ -101,21 +104,29 @@ export function createWorkbenchFactsStore(options = {}, actor = null) {
 
 async function durableTraceSnapshot(runtimeStore, traceId) {
   if (!runtimeStore || typeof runtimeStore.queryAgentTraceEvents !== "function") return null;
+  const safeId = safeTraceId(traceId);
+  if (!safeId) return null;
+  const cached = terminalDurableTraceCache.get(safeId);
+  if (cached) {
+    terminalDurableTraceCache.delete(safeId);
+    terminalDurableTraceCache.set(safeId, cached);
+    return cached;
+  }
   let result;
   try {
-    result = await runtimeStore.queryAgentTraceEvents({ traceId });
+    result = await runtimeStore.queryAgentTraceEvents({ traceId: safeId });
   } catch (error) {
-    return projectionStoreUnavailableTrace(traceId, error);
+    return projectionStoreUnavailableTrace(safeId, error);
   }
   const events = Array.isArray(result?.events) ? result.events : [];
   if (events.length === 0) return null;
-  const normalizedEvents = events.map((event, index) => ({ ...event, traceId, seq: eventSeq(event, index) }));
+  const normalizedEvents = events.map((event, index) => ({ ...event, traceId: safeId, seq: eventSeq(event, index) }));
   const firstEvent = normalizedEvents[0] ?? null;
   const lastEvent = normalizedEvents.at(-1) ?? null;
   const status = durableTraceStatus(normalizedEvents);
   const terminalEvidence = traceTerminalEvidence({ events: normalizedEvents, status });
-  return {
-    traceId,
+  const snapshot = {
+    traceId: safeId,
     status,
     createdAt: firstEvent?.createdAt ?? null,
     updatedAt: lastEvent?.createdAt ?? firstEvent?.createdAt ?? null,
@@ -130,6 +141,19 @@ async function durableTraceSnapshot(runtimeStore, traceId) {
     outputTruncated: normalizedEvents.some((event) => event.outputTruncated === true),
     valuesPrinted: false
   };
+  rememberTerminalDurableTrace(snapshot);
+  return snapshot;
+}
+
+function rememberTerminalDurableTrace(snapshot) {
+  const traceId = safeTraceId(snapshot?.traceId);
+  if (!traceId || !TERMINAL_STATUSES.has(normalizeStatus(snapshot?.status))) return;
+  terminalDurableTraceCache.delete(traceId);
+  terminalDurableTraceCache.set(traceId, snapshot);
+  while (terminalDurableTraceCache.size > TERMINAL_DURABLE_TRACE_CACHE_MAX) {
+    const oldest = terminalDurableTraceCache.keys().next().value;
+    terminalDurableTraceCache.delete(oldest);
+  }
 }
 
 function projectionStoreUnavailableTrace(traceId, error) {