diff --git a/app/src/api/file.ts b/app/src/api/file.ts
index 53602a8..cdfe123 100644
--- a/app/src/api/file.ts
+++ b/app/src/api/file.ts
@@ -3,10 +3,8 @@ import { apiCall } from './api';
 import {
   FileNode,
   isFileNode,
-  isLastOpenedFileResponse,
   isLookupResponse,
   isSaveFileResponse,
-  LastOpenedFileResponse,
   LookupResponse,
   SaveFileResponse,
 } from '@/types/fileApi';
@@ -138,11 +136,10 @@ export const getLastOpenedFile = async (
     `${API_BASE_URL}/workspaces/${encodeURIComponent(workspaceName)}/files/last`
   );
   const data = await response.json();
-  if (!isLastOpenedFileResponse(data)) {
+  if (!('lastOpenedFilePath' in data)) {
     throw new Error('Invalid last opened file response received from API');
   }
-  const lastOpenedFileResponse = data as LastOpenedFileResponse;
-  return lastOpenedFileResponse.lastOpenedFilePath;
+  return data.lastOpenedFilePath;
 };
 
 /**
diff --git a/app/src/hooks/useLastOpenedFile.js b/app/src/hooks/useLastOpenedFile.ts
similarity index 62%
rename from app/src/hooks/useLastOpenedFile.js
rename to app/src/hooks/useLastOpenedFile.ts
index eee230e..4422818 100644
--- a/app/src/hooks/useLastOpenedFile.js
+++ b/app/src/hooks/useLastOpenedFile.ts
@@ -1,16 +1,21 @@
 import { useCallback } from 'react';
-import { getLastOpenedFile, updateLastOpenedFile } from '../api/git';
+import { getLastOpenedFile, updateLastOpenedFile } from '../api/file';
 import { useWorkspace } from '../contexts/WorkspaceContext';
 
-export const useLastOpenedFile = () => {
+interface UseLastOpenedFileResult {
+  loadLastOpenedFile: () => Promise<string | null>;
+  saveLastOpenedFile: (filePath: string) => Promise<void>;
+}
+
+export const useLastOpenedFile = (): UseLastOpenedFileResult => {
   const { currentWorkspace } = useWorkspace();
 
-  const loadLastOpenedFile = useCallback(async () => {
+  const loadLastOpenedFile = useCallback(async (): Promise<string | null> => {
     if (!currentWorkspace) return null;
 
     try {
-      const response = await getLastOpenedFile(currentWorkspace.name);
-      return response.lastOpenedFilePath || null;
+      const response: string = await getLastOpenedFile(currentWorkspace.name);
+      return response || null;
     } catch (error) {
       console.error('Failed to load last opened file:', error);
       return null;
@@ -18,7 +23,7 @@ export const useLastOpenedFile = () => {
   }, [currentWorkspace]);
 
   const saveLastOpenedFile = useCallback(
-    async (filePath) => {
+    async (filePath: string): Promise<void> => {
       if (!currentWorkspace) return;
 
       try {
diff --git a/app/src/types/fileApi.ts b/app/src/types/fileApi.ts
index ffe0c49..70d4261 100644
--- a/app/src/types/fileApi.ts
+++ b/app/src/types/fileApi.ts
@@ -31,21 +31,6 @@ export function isSaveFileResponse(obj: unknown): obj is SaveFileResponse {
   );
 }
 
-export interface LastOpenedFileResponse {
-  lastOpenedFilePath: string;
-}
-
-export function isLastOpenedFileResponse(
-  obj: unknown
-): obj is LastOpenedFileResponse {
-  return (
-    typeof obj === 'object' &&
-    obj !== null &&
-    'lastOpenedFilePath' in obj &&
-    typeof (obj as LastOpenedFileResponse).lastOpenedFilePath === 'string'
-  );
-}
-
 export interface UpdateLastOpenedFileRequest {
   filePath: string;
 }