diff --git a/src/resources/extensions/gsd/auto-dashboard.ts b/src/resources/extensions/gsd/auto-dashboard.ts
index 5f44e763e..f2c77d168 100644
--- a/src/resources/extensions/gsd/auto-dashboard.ts
+++ b/src/resources/extensions/gsd/auto-dashboard.ts
@@ -390,6 +390,8 @@ export interface WidgetStateAccessors {
   getCmdCtx(): ExtensionCommandContext | null;
   getBasePath(): string;
   isVerbose(): boolean;
+  /** True while newSession() is in-flight — render must not access session state. */
+  isSessionSwitching(): boolean;
 }
 
 export function updateProgressWidget(
@@ -460,6 +462,14 @@ export function updateProgressWidget(
       render(width: number): string[] {
         if (cachedLines && cachedWidth === width) return cachedLines;
 
+        // While newSession() is in-flight, session state is mid-mutation.
+        // Accessing cmdCtx.sessionManager or cmdCtx.getContextUsage() can
+        // block the render loop and freeze the TUI. Return the last cached
+        // frame (or an empty frame on first render) until the switch settles.
+        if (accessors.isSessionSwitching()) {
+          return cachedLines ?? [];
+        }
+
         const ui = makeUI(theme, width);
         const lines: string[] = [];
         const pad = INDENT.base;
diff --git a/src/resources/extensions/gsd/auto.ts b/src/resources/extensions/gsd/auto.ts
index 89e227449..495dca4b1 100644
--- a/src/resources/extensions/gsd/auto.ts
+++ b/src/resources/extensions/gsd/auto.ts
@@ -195,7 +195,7 @@ import {
   postUnitPostVerification,
 } from "./auto-post-unit.js";
 import { bootstrapAutoSession, type BootstrapDeps } from "./auto-start.js";
-import { autoLoop, resolveAgentEnd, type LoopDeps } from "./auto-loop.js";
+import { autoLoop, resolveAgentEnd, isSessionSwitchInFlight, type LoopDeps } from "./auto-loop.js";
 import {
   WorktreeResolver,
   type WorktreeResolverDeps,
@@ -1129,6 +1129,7 @@ const widgetStateAccessors: WidgetStateAccessors = {
   getCmdCtx: () => s.cmdCtx,
   getBasePath: () => s.basePath,
   isVerbose: () => s.verbose,
+  isSessionSwitching: isSessionSwitchInFlight,
 };
 
 // ─── Preconditions ────────────────────────────────────────────────────────────