diff --git a/src/main/services/infrastructure/LocalFileSystemProvider.ts b/src/main/services/infrastructure/LocalFileSystemProvider.ts
index 9d7ee499..ceb5a3fb 100644
--- a/src/main/services/infrastructure/LocalFileSystemProvider.ts
+++ b/src/main/services/infrastructure/LocalFileSystemProvider.ts
@@ -43,11 +43,25 @@ export class LocalFileSystemProvider implements FileSystemProvider {
 
   async readdir(dirPath: string): Promise<FsDirent[]> {
     const entries = await fs.promises.readdir(dirPath, { withFileTypes: true });
-    return entries.map((entry) => ({
-      name: entry.name,
-      isFile: () => entry.isFile(),
-      isDirectory: () => entry.isDirectory(),
-    }));
+    // Stat all entries concurrently to populate mtimeMs, used by SessionSearcher's
+    // mtime-based cache invalidation. Failures are silently ignored (mtimeMs stays undefined).
+    return Promise.all(
+      entries.map(async (entry) => {
+        let mtimeMs: number | undefined;
+        try {
+          const stat = await fs.promises.stat(`${dirPath}/${entry.name}`);
+          mtimeMs = stat.mtimeMs;
+        } catch {
+          // ignore
+        }
+        return {
+          name: entry.name,
+          mtimeMs,
+          isFile: () => entry.isFile(),
+          isDirectory: () => entry.isDirectory(),
+        };
+      })
+    );
   }
 
   createReadStream(filePath: string, opts?: ReadStreamOptions): fs.ReadStream {
diff --git a/src/renderer/store/slices/sessionDetailSlice.ts b/src/renderer/store/slices/sessionDetailSlice.ts
index 7eb2dd8c..9a158f49 100644
--- a/src/renderer/store/slices/sessionDetailSlice.ts
+++ b/src/renderer/store/slices/sessionDetailSlice.ts
@@ -197,16 +197,19 @@ export const createSessionDetailSlice: StateCreator<AppState, [], [], SessionDet
       let claudeMdStats: Map<string, ClaudeMdStats> | null = null;
       let contextStats: Map<string, ContextStats> | null = null;
       let phaseInfo: ContextPhaseInfo | null = null;
-      // Fetch agent configs from .claude/agents/ (only when project changes)
+      // Fetch agent configs from .claude/agents/ (only when project changes).
+      // Fire-and-forget: don't block transcript rendering — color badges update async.
       if (connectionMode !== 'ssh' && projectRoot && projectRoot !== agentConfigsCachedForProject) {
-        try {
-          const configs = await api.readAgentConfigs(projectRoot);
-          if (requestGeneration !== sessionDetailFetchGeneration) return;
-          agentConfigsCachedForProject = projectRoot;
-          set({ agentConfigs: configs });
-        } catch (err) {
-          logger.error('Failed to read agent configs:', err);
-        }
+        agentConfigsCachedForProject = projectRoot; // Optimistic set to prevent duplicate fetches
+        api
+          .readAgentConfigs(projectRoot)
+          .then((configs) => {
+            set({ agentConfigs: configs });
+          })
+          .catch((err) => {
+            logger.error('Failed to read agent configs:', err);
+            agentConfigsCachedForProject = ''; // Reset so it retries next time
+          });
       }
 
       if (connectionMode !== 'ssh' && conversation?.items) {