diff --git a/internal/cloud/access-control.test.ts b/internal/cloud/access-control.test.ts
index 7809ce41..f45f2c0f 100644
--- a/internal/cloud/access-control.test.ts
+++ b/internal/cloud/access-control.test.ts
@@ -865,6 +865,122 @@ test("workbench workspace terminal status sync preserves a newer selected conver
   }
 });
 
+test("manual Code Agent session select restores running active trace", async () => {
+  const accessController = createAccessController({
+    env: {
+      HWLAB_ACCESS_CONTROL_REQUIRED: "1",
+      HWLAB_BOOTSTRAP_ADMIN_USERNAME: "admin",
+      HWLAB_BOOTSTRAP_ADMIN_PASSWORD: "admin-pass"
+    },
+    now: () => "2026-06-01T00:00:00.000Z"
+  });
+  const server = createCloudApiServer({
+    env: {
+      HWLAB_ACCESS_CONTROL_REQUIRED: "1",
+      HWLAB_BOOTSTRAP_ADMIN_USERNAME: "admin",
+      HWLAB_BOOTSTRAP_ADMIN_PASSWORD: "admin-pass",
+      HWLAB_CODE_AGENT_DEFAULT_PROVIDER_PROFILE: "minimax-m3"
+    },
+    accessController,
+    now: () => "2026-06-01T00:00:00.000Z"
+  });
+  await new Promise((resolve) => server.listen(0, "127.0.0.1", resolve));
+
+  try {
+    const { port } = server.address();
+    const adminLogin = await postJson(port, "/auth/login", { username: "admin", password: "admin-pass" });
+    const alice = await postJson(port, "/v1/admin/users", { username: "alice-ws-issue810", password: "alice-pass" }, adminLogin.cookie);
+    assert.equal(alice.status, 201);
+    const aliceLogin = await postJson(port, "/auth/login", { username: "alice-ws-issue810", password: "alice-pass" });
+    const workspace = await getJson(port, "/v1/workbench/workspace?projectId=prj_device_pod_workbench", aliceLogin.cookie);
+    assert.equal(workspace.status, 200);
+
+    await accessController.recordAgentSessionOwner({
+      ownerUserId: alice.body.user.id,
+      ownerRole: "user",
+      sessionId: "ses_issue810_running",
+      projectId: "prj_device_pod_workbench",
+      agentId: "hwlab-code-agent",
+      status: "running",
+      conversationId: "cnv_issue810_running",
+      threadId: "thread-issue-810-running",
+      traceId: "trc_issue810_running",
+      session: {
+        source: "test-running-session",
+        providerProfile: "minimax-m3",
+        sessionStatus: "running",
+        currentTraceId: "trc_issue810_running",
+        agentRun: {
+          runId: "run_issue810_running",
+          commandId: "cmd_issue810_running",
+          runStatus: "running",
+          commandState: "running",
+          backendProfile: "minimax-m3"
+        },
+        valuesRedacted: true,
+        secretMaterialStored: false
+      }
+    });
+    await accessController.recordAgentSessionOwner({
+      ownerUserId: alice.body.user.id,
+      ownerRole: "user",
+      sessionId: "ses_issue810_idle",
+      projectId: "prj_device_pod_workbench",
+      agentId: "hwlab-code-agent",
+      status: "idle",
+      conversationId: "cnv_issue810_idle",
+      threadId: "thread-issue-810-idle",
+      traceId: null,
+      session: {
+        source: "test-idle-session",
+        providerProfile: "minimax-m3",
+        sessionStatus: "idle",
+        valuesRedacted: true,
+        secretMaterialStored: false
+      }
+    });
+
+    const selectedIdle = await postJson(port, "/v1/agent/sessions/ses_issue810_idle/select", {
+      projectId: "prj_device_pod_workbench",
+      workspaceId: workspace.body.workspace.workspaceId,
+      updatedByClient: "test-suite"
+    }, aliceLogin.cookie);
+    assert.equal(selectedIdle.status, 200);
+    assert.equal(selectedIdle.body.workspace.selectedConversationId, "cnv_issue810_idle");
+    assert.equal(selectedIdle.body.workspace.selectedAgentSessionId, "ses_issue810_idle");
+    assert.equal(selectedIdle.body.workspace.activeTraceId, null);
+
+    const selectedRunning = await postJson(port, "/v1/agent/sessions/ses_issue810_running/select", {
+      projectId: "prj_device_pod_workbench",
+      workspaceId: workspace.body.workspace.workspaceId,
+      updatedByClient: "test-suite"
+    }, aliceLogin.cookie);
+    assert.equal(selectedRunning.status, 200);
+    assert.equal(selectedRunning.body.status, "selected");
+    assert.equal(selectedRunning.body.session.sessionId, "ses_issue810_running");
+    assert.equal(selectedRunning.body.session.status, "running");
+    assert.equal(selectedRunning.body.session.lastTraceId, "trc_issue810_running");
+    assert.equal(selectedRunning.body.workspace.selectedConversationId, "cnv_issue810_running");
+    assert.equal(selectedRunning.body.workspace.selectedAgentSessionId, "ses_issue810_running");
+    assert.equal(selectedRunning.body.workspace.activeTraceId, "trc_issue810_running");
+    assert.equal(selectedRunning.body.workspace.workspace.activeTraceId, "trc_issue810_running");
+    assert.equal(selectedRunning.body.workspace.workspace.lastTraceId, "trc_issue810_running");
+    assert.equal(selectedRunning.body.workspace.workspace.sessionStatus, "running");
+    assert.equal(selectedRunning.body.workspace.workspace.providerProfile, "minimax-m3");
+
+    const restored = await getJson(port, "/v1/workbench/workspace?projectId=prj_device_pod_workbench", aliceLogin.cookie);
+    assert.equal(restored.status, 200);
+    assert.equal(restored.body.workspace.selectedConversationId, "cnv_issue810_running");
+    assert.equal(restored.body.workspace.selectedAgentSessionId, "ses_issue810_running");
+    assert.equal(restored.body.workspace.activeTraceId, "trc_issue810_running");
+    assert.equal(restored.body.workspace.workspace.activeTraceId, "trc_issue810_running");
+    assert.equal(restored.body.workspace.workspace.lastTraceId, "trc_issue810_running");
+    assert.equal(restored.body.workspace.workspace.sessionStatus, "running");
+  } finally {
+    await new Promise((resolve, reject) => server.close((error) => (error ? reject(error) : resolve())));
+  }
+});
+
 test("workbench workspace clears stale continuation after AgentRun thread resume failure", async () => {
   const staleThreadId = "019e0000-0000-7000-8000-000000000195";
   const agentRunCalls = [];
diff --git a/internal/cloud/server-code-agent-http.ts b/internal/cloud/server-code-agent-http.ts
index f428886b..97b135d1 100644
--- a/internal/cloud/server-code-agent-http.ts
+++ b/internal/cloud/server-code-agent-http.ts
@@ -333,6 +333,8 @@ async function updateManualSessionWorkspace({ params = {}, options = {}, session
     ? await store.getWorkspaceForUser?.({ workspaceId, ownerUserId: options.actor.id, actorRole: options.actor.role })
     : await store.getOrCreateDefaultWorkspace?.({ ownerUserId: options.actor.id, projectId });
   if (!current) return null;
+  const selectedActiveTraceId = manualSessionSelectableActiveTraceId(session);
+  const selectedLastTraceId = safeTraceId(session.lastTraceId) || selectedActiveTraceId || null;
   const updated = await store.updateWorkspace?.({
     workspaceId: current.id,
     ownerUserId: options.actor.id,
@@ -343,13 +345,14 @@ async function updateManualSessionWorkspace({ params = {}, options = {}, session
     selectedConversationId: session.conversationId,
     selectedAgentSessionId: session.id,
     selectedDevicePodId: current.selectedDevicePodId,
-    activeTraceId: null,
+    activeTraceId: selectedActiveTraceId,
     providerProfile,
     patch: {
       ...(current.workspace && typeof current.workspace === "object" ? current.workspace : {}),
       selectedConversationId: session.conversationId,
       selectedAgentSessionId: session.id,
-      activeTraceId: null,
+      activeTraceId: selectedActiveTraceId,
+      ...(selectedLastTraceId ? { lastTraceId: selectedLastTraceId } : {}),
       sessionStatus: session.status,
       threadId: safeOpaqueId(session.threadId) || null,
       providerProfile,
@@ -368,6 +371,31 @@ async function updateManualSessionWorkspace({ params = {}, options = {}, session
   return updated ?? current;
 }
 
+function manualSessionSelectableActiveTraceId(session = {}) {
+  if (!manualSessionHasRunningTraceStatus(session)) return null;
+  return safeTraceId(
+    session.currentTraceId
+      ?? session.session?.currentTraceId
+      ?? session.session?.traceId
+      ?? session.session?.runnerTrace?.traceId
+      ?? session.session?.agentRun?.traceId
+  ) || safeTraceId(session.lastTraceId) || null;
+}
+
+function manualSessionHasRunningTraceStatus(session = {}) {
+  return [
+    session.status,
+    session.session?.sessionStatus,
+    session.session?.lifecycleStatus,
+    session.session?.runnerTrace?.sessionStatus,
+    session.session?.runnerTrace?.status,
+    session.session?.agentRun?.runStatus,
+    session.session?.agentRun?.commandState,
+    session.session?.agentRun?.terminalStatus
+  ].map((value) => String(value ?? "").trim().toLowerCase().replace(/_/gu, "-"))
+    .some((value) => ["running", "busy", "pending", "creating"].includes(value));
+}
+
 function publicManualAgentSession(session) {
   if (!session || typeof session !== "object") return null;
   return {