diff --git a/packages/app/src/screens/workspace/workspace-screen.tsx b/packages/app/src/screens/workspace/workspace-screen.tsx
index ffe001286..60356a289 100644
--- a/packages/app/src/screens/workspace/workspace-screen.tsx
+++ b/packages/app/src/screens/workspace/workspace-screen.tsx
@@ -133,9 +133,10 @@ import {
 } from "@/screens/workspace/workspace-route-state";
 import { renderWorkspaceRouteGate } from "@/screens/workspace/workspace-route-state-views";
 import {
+  buildWorkspaceTabSnapshot,
   deriveWorkspaceAgentVisibility,
   workspaceAgentVisibilityEqual,
-} from "@/screens/workspace/workspace-agent-visibility";
+} from "@/workspace-tabs/agent-visibility";
 import { deriveWorkspacePaneState } from "@/screens/workspace/workspace-pane-state";
 import {
   buildWorkspacePaneContentModel,
@@ -1919,16 +1920,17 @@ function WorkspaceScreenContent({
       return pending?.serverId === normalizedServerId && pending.lifecycle === "active";
     });
 
-    reconcileWorkspaceTabs(persistenceKey, {
-      agentsHydrated: hasHydratedAgents,
-      terminalsHydrated: terminalsQuery.isSuccess,
-      activeAgentIds: Array.from(workspaceAgentVisibility.activeAgentIds),
-      autoOpenAgentIds: Array.from(workspaceAgentVisibility.autoOpenAgentIds),
-      knownAgentIds: Array.from(workspaceAgentVisibility.knownAgentIds),
-      knownTerminalIds,
-      standaloneTerminalIds,
-      hasActivePendingDraftCreate: hasActivePendingDraftCreateInWorkspace,
-    });
+    reconcileWorkspaceTabs(
+      persistenceKey,
+      buildWorkspaceTabSnapshot({
+        agentVisibility: workspaceAgentVisibility,
+        agentsHydrated: hasHydratedAgents,
+        terminalsHydrated: terminalsQuery.isSuccess,
+        knownTerminalIds,
+        standaloneTerminalIds,
+        hasActivePendingDraftCreate: hasActivePendingDraftCreateInWorkspace,
+      }),
+    );
   }, [
     hasHydratedAgents,
     hasHydratedWorkspaceLayoutStore,
diff --git a/packages/app/src/stores/workspace-subagents-integration.test.ts b/packages/app/src/stores/workspace-subagents-integration.test.ts
index 37af647b3..1b3499111 100644
--- a/packages/app/src/stores/workspace-subagents-integration.test.ts
+++ b/packages/app/src/stores/workspace-subagents-integration.test.ts
@@ -1,9 +1,10 @@
 import type { DaemonClient } from "@server/client/daemon-client";
 import { afterEach, describe, expect, it, vi } from "vitest";
 import {
+  buildWorkspaceTabSnapshot,
   deriveWorkspaceAgentVisibility,
   type WorkspaceAgentVisibility,
-} from "@/screens/workspace/workspace-agent-visibility";
+} from "@/workspace-tabs/agent-visibility";
 import { selectSubagentsForParent } from "@/subagents";
 import { buildWorkspaceTabPersistenceKey, useWorkspaceLayoutStore } from "./workspace-layout-store";
 import { useSessionStore, type Agent } from "./session-store";
@@ -151,15 +152,17 @@ function deriveVisibilityFromSession(): WorkspaceAgentVisibility {
 }
 
 function reconcileWorkspaceTabs(workspaceKey: string, visibility: WorkspaceAgentVisibility): void {
-  useWorkspaceLayoutStore.getState().reconcileTabs(workspaceKey, {
-    agentsHydrated: true,
-    terminalsHydrated: true,
-    activeAgentIds: visibility.activeAgentIds,
-    autoOpenAgentIds: visibility.autoOpenAgentIds,
-    knownAgentIds: visibility.knownAgentIds,
-    standaloneTerminalIds: [],
-    hasActivePendingDraftCreate: false,
-  });
+  useWorkspaceLayoutStore.getState().reconcileTabs(
+    workspaceKey,
+    buildWorkspaceTabSnapshot({
+      agentVisibility: visibility,
+      agentsHydrated: true,
+      terminalsHydrated: true,
+      knownTerminalIds: [],
+      standaloneTerminalIds: [],
+      hasActivePendingDraftCreate: false,
+    }),
+  );
 }
 
 function getWorkspaceTabIds(workspaceKey: string): string[] {
diff --git a/packages/app/src/subagents/policies.ts b/packages/app/src/subagents/policies.ts
index ae7597691..b8a29d07d 100644
--- a/packages/app/src/subagents/policies.ts
+++ b/packages/app/src/subagents/policies.ts
@@ -1,5 +1,5 @@
 // Pure-data entry point for callers that don't want React Native deps in
-// their dependency graph (e.g. workspace-agent-visibility.ts is plain JS
+// their dependency graph (e.g. workspace-tabs/agent-visibility.ts is plain
 // data derivation and its tests run without an RN environment).
 //
 // The full module entry `@/subagents` re-exports these too, alongside the
diff --git a/packages/app/src/screens/workspace/workspace-agent-visibility.test.ts b/packages/app/src/workspace-tabs/agent-visibility.test.ts
similarity index 90%
rename from packages/app/src/screens/workspace/workspace-agent-visibility.test.ts
rename to packages/app/src/workspace-tabs/agent-visibility.test.ts
index f02dc4daa..3e4c9bb36 100644
--- a/packages/app/src/screens/workspace/workspace-agent-visibility.test.ts
+++ b/packages/app/src/workspace-tabs/agent-visibility.test.ts
@@ -1,10 +1,11 @@
 import { describe, expect, it } from "vitest";
 import type { Agent } from "@/stores/session-store";
 import {
+  buildWorkspaceTabSnapshot,
   deriveWorkspaceAgentVisibility,
   shouldPruneWorkspaceAgentTab,
   workspaceAgentVisibilityEqual,
-} from "@/screens/workspace/workspace-agent-visibility";
+} from "@/workspace-tabs/agent-visibility";
 
 function makeAgent(input: {
   id: string;
@@ -265,6 +266,34 @@ describe("workspace agent visibility", () => {
     expect(result.knownAgentIds).toEqual(new Set(["recent-agent"]));
   });
 
+  it("builds the tab reconciliation snapshot without callers unpacking agent visibility", () => {
+    const agentVisibility = {
+      activeAgentIds: new Set(["active-agent"]),
+      autoOpenAgentIds: new Set(["root-agent"]),
+      knownAgentIds: new Set(["active-agent", "archived-agent"]),
+    };
+
+    expect(
+      buildWorkspaceTabSnapshot({
+        agentVisibility,
+        agentsHydrated: true,
+        terminalsHydrated: true,
+        knownTerminalIds: ["terminal-1", "script-terminal"],
+        standaloneTerminalIds: ["terminal-1"],
+        hasActivePendingDraftCreate: false,
+      }),
+    ).toEqual({
+      agentsHydrated: true,
+      terminalsHydrated: true,
+      activeAgentIds: agentVisibility.activeAgentIds,
+      autoOpenAgentIds: agentVisibility.autoOpenAgentIds,
+      knownAgentIds: agentVisibility.knownAgentIds,
+      knownTerminalIds: ["terminal-1", "script-terminal"],
+      standaloneTerminalIds: ["terminal-1"],
+      hasActivePendingDraftCreate: false,
+    });
+  });
+
   describe("workspaceAgentVisibilityEqual", () => {
     it("returns true for identical sets", () => {
       const a = {
diff --git a/packages/app/src/screens/workspace/workspace-agent-visibility.ts b/packages/app/src/workspace-tabs/agent-visibility.ts
similarity index 76%
rename from packages/app/src/screens/workspace/workspace-agent-visibility.ts
rename to packages/app/src/workspace-tabs/agent-visibility.ts
index f0ad8c1fb..45235f857 100644
--- a/packages/app/src/screens/workspace/workspace-agent-visibility.ts
+++ b/packages/app/src/workspace-tabs/agent-visibility.ts
@@ -1,4 +1,5 @@
 import type { Agent } from "@/stores/session-store";
+import type { WorkspaceTabSnapshot } from "@/stores/workspace-layout-actions";
 import { shouldAutoOpenAgentTab } from "@/subagents/policies";
 import { normalizeWorkspacePath } from "@/utils/workspace-identity";
 
@@ -52,6 +53,26 @@ export function deriveWorkspaceAgentVisibility(input: {
   return { activeAgentIds, autoOpenAgentIds, knownAgentIds };
 }
 
+export function buildWorkspaceTabSnapshot(input: {
+  agentVisibility: WorkspaceAgentVisibility;
+  agentsHydrated: boolean;
+  terminalsHydrated: boolean;
+  knownTerminalIds: Iterable<string>;
+  standaloneTerminalIds: Iterable<string>;
+  hasActivePendingDraftCreate: boolean;
+}): WorkspaceTabSnapshot {
+  return {
+    agentsHydrated: input.agentsHydrated,
+    terminalsHydrated: input.terminalsHydrated,
+    activeAgentIds: input.agentVisibility.activeAgentIds,
+    autoOpenAgentIds: input.agentVisibility.autoOpenAgentIds,
+    knownAgentIds: input.agentVisibility.knownAgentIds,
+    knownTerminalIds: input.knownTerminalIds,
+    standaloneTerminalIds: input.standaloneTerminalIds,
+    hasActivePendingDraftCreate: input.hasActivePendingDraftCreate,
+  };
+}
+
 export function workspaceAgentVisibilityEqual(
   a: WorkspaceAgentVisibility,
   b: WorkspaceAgentVisibility,