diff --git a/src/services/code-index/__tests__/cache-manager.spec.ts b/src/services/code-index/__tests__/cache-manager.spec.ts
index 27408fdf33..e61a92f3cc 100644
--- a/src/services/code-index/__tests__/cache-manager.spec.ts
+++ b/src/services/code-index/__tests__/cache-manager.spec.ts
@@ -4,6 +4,14 @@ import { createHash } from "crypto"
 import debounce from "lodash.debounce"
 import { CacheManager } from "../cache-manager"
 
+// Mock safeWriteJson utility
+vitest.mock("../../../utils/safeWriteJson", () => ({
+	safeWriteJson: vitest.fn().mockResolvedValue(undefined),
+}))
+
+// Import the mocked version
+import { safeWriteJson } from "../../../utils/safeWriteJson"
+
 // Mock vscode
 vitest.mock("vscode", () => ({
 	Uri: {
@@ -89,7 +97,7 @@ describe("CacheManager", () => {
 			cacheManager.updateHash(filePath, hash)
 
 			expect(cacheManager.getHash(filePath)).toBe(hash)
-			expect(vscode.workspace.fs.writeFile).toHaveBeenCalled()
+			expect(safeWriteJson).toHaveBeenCalled()
 		})
 
 		it("should delete hash and trigger save", () => {
@@ -100,7 +108,7 @@ describe("CacheManager", () => {
 			cacheManager.deleteHash(filePath)
 
 			expect(cacheManager.getHash(filePath)).toBeUndefined()
-			expect(vscode.workspace.fs.writeFile).toHaveBeenCalled()
+			expect(safeWriteJson).toHaveBeenCalled()
 		})
 
 		it("should return shallow copy of hashes", () => {
@@ -125,18 +133,16 @@ describe("CacheManager", () => {
 
 			cacheManager.updateHash(filePath, hash)
 
-			expect(vscode.workspace.fs.writeFile).toHaveBeenCalledWith(mockCachePath, expect.any(Uint8Array))
+			expect(safeWriteJson).toHaveBeenCalledWith(mockCachePath.fsPath, expect.any(Object))
 
 			// Verify the saved data
-			const savedData = JSON.parse(
-				Buffer.from((vscode.workspace.fs.writeFile as Mock).mock.calls[0][1]).toString(),
-			)
+			const savedData = (safeWriteJson as Mock).mock.calls[0][1]
 			expect(savedData).toEqual({ [filePath]: hash })
 		})
 
 		it("should handle save errors gracefully", async () => {
 			const consoleErrorSpy = vitest.spyOn(console, "error").mockImplementation(() => {})
-			;(vscode.workspace.fs.writeFile as Mock).mockRejectedValue(new Error("Save failed"))
+			;(safeWriteJson as Mock).mockRejectedValue(new Error("Save failed"))
 
 			cacheManager.updateHash("test.ts", "hash")
 
@@ -153,19 +159,19 @@ describe("CacheManager", () => {
 		it("should clear cache file and reset state", async () => {
 			cacheManager.updateHash("test.ts", "hash")
 
-			// Reset the mock to ensure writeFile succeeds for clearCacheFile
-			;(vscode.workspace.fs.writeFile as Mock).mockClear()
-			;(vscode.workspace.fs.writeFile as Mock).mockResolvedValue(undefined)
+			// Reset the mock to ensure safeWriteJson succeeds for clearCacheFile
+			;(safeWriteJson as Mock).mockClear()
+			;(safeWriteJson as Mock).mockResolvedValue(undefined)
 
 			await cacheManager.clearCacheFile()
 
-			expect(vscode.workspace.fs.writeFile).toHaveBeenCalledWith(mockCachePath, Buffer.from("{}"))
+			expect(safeWriteJson).toHaveBeenCalledWith(mockCachePath.fsPath, {})
 			expect(cacheManager.getAllHashes()).toEqual({})
 		})
 
 		it("should handle clear errors gracefully", async () => {
 			const consoleErrorSpy = vitest.spyOn(console, "error").mockImplementation(() => {})
-			;(vscode.workspace.fs.writeFile as Mock).mockRejectedValue(new Error("Save failed"))
+			;(safeWriteJson as Mock).mockRejectedValue(new Error("Save failed"))
 
 			await cacheManager.clearCacheFile()