diff --git a/packages/cli-repl/src/crypt-library-paths.ts b/packages/cli-repl/src/crypt-library-paths.ts
index 6eebd75e7..d3b1ac1e6 100644
--- a/packages/cli-repl/src/crypt-library-paths.ts
+++ b/packages/cli-repl/src/crypt-library-paths.ts
@@ -1,16 +1,21 @@
 import path from 'path';
 import { promises as fs, constants as fsConstants } from 'fs';
 import type { MongoshBus } from '@mongosh/types';
+import type { AutoEncryptionOptions } from 'mongodb';
 
-export const SHARED_LIBRARY_SUFFIX =
+type SharedObjectSuffix = 'so' | 'dylib' | 'dll';
+export const SHARED_LIBRARY_SUFFIX: SharedObjectSuffix =
   process.platform === 'win32'
     ? 'dll'
     : process.platform === 'darwin'
     ? 'dylib'
     : 'so';
+export type CryptSharedLibPath = NonNullable<
+  NonNullable<AutoEncryptionOptions['extraOptions']>['cryptSharedLibPath']
+>;
 
 export interface CryptLibraryPathResult {
-  cryptSharedLibPath?: string;
+  cryptSharedLibPath?: CryptSharedLibPath;
   expectedVersion?: { version: bigint; versionStr: string };
 }
 
@@ -54,7 +59,10 @@ export async function getCryptLibraryPaths(
       ),
       // Location of the shared library in the zip and tgz packages
       path.resolve(bindir, `mongosh_crypt_v1.${SHARED_LIBRARY_SUFFIX}`),
-    ]) {
+      // NB: The types here intentionally mismatch, as we rename the
+      // library file to avoid conflicts with system installations of
+      // the crypt_shared library.
+    ] as CryptSharedLibPath[]) {
       try {
         const permissionsMismatch = await ensureMatchingPermissions(
           libraryCandidate,