diff --git a/src/core/cli.ts b/src/core/cli.ts
index c3ecd1b..bb2d92e 100644
--- a/src/core/cli.ts
+++ b/src/core/cli.ts
@@ -282,32 +282,28 @@ instead of "${definition.name}"`);
     let targetPath: string | undefined;
     let targetModule: CommandModule | undefined;
 
-    let contexts: SubcommandSearchContext[] = await v.map(
-      this.roots,
-      async root => {
-        let path: string | undefined = Path.join(root.path, 'default.js');
-        path = (await existsFile(path)) ? path : undefined;
+    let contexts: SubcommandSearchContext[] = this.roots.map(root => {
+      let path = existsFile(root.path);
 
-        let module: CommandModule | undefined;
+      let module: CommandModule | undefined;
 
-        if (path) {
-          module = require(path) as CommandModule;
+      if (path) {
+        module = require(path) as CommandModule;
 
-          if (module.default || !targetPath) {
-            targetPath = path;
-            targetModule = module;
-          }
+        if (module.default || !targetPath) {
+          targetPath = path;
+          targetModule = module;
         }
+      }
 
-        return {
-          label: root.label,
-          name: this.name,
-          searchBase: root.path,
-          path,
-          module,
-        };
-      },
-    );
+      return {
+        label: root.label,
+        name: this.name,
+        searchBase: root.path,
+        path,
+        module,
+      };
+    });
 
     for (let i = argsIndex; i < argv.length && contexts.length; i++) {
       let possibleCommandName = argv[i];
@@ -415,18 +411,12 @@ instead of "${definition.name}"`);
   private static async findEntryBySearchBase(
     searchBase: string,
   ): Promise<CommandEntry | undefined> {
-    let possiblePaths = [
-      `${searchBase}.js`,
-      Path.join(searchBase, 'default.js'),
-    ];
-
-    for (let possiblePath of possiblePaths) {
-      if (await existsFile(possiblePath)) {
-        return {
-          path: possiblePath,
-          module: require(possiblePath) as CommandModule,
-        };
-      }
+    const srcFile = existsFile(searchBase);
+    if (srcFile !== undefined) {
+      return {
+        path: srcFile,
+        module: require(srcFile) as CommandModule,
+      };
     }
 
     if (await existsDir(searchBase)) {
diff --git a/src/core/command/help.ts b/src/core/command/help.ts
index 04c61c2..42ed9bd 100644
--- a/src/core/command/help.ts
+++ b/src/core/command/help.ts
@@ -13,6 +13,7 @@ import {CLI, CommandModule} from '../cli';
 import {
   buildTableOutput,
   existsDir,
+  existsFile,
   indent,
   safeStat,
 } from '../../internal-util';
@@ -102,18 +103,22 @@ export class HelpInfo implements Printable {
       let names = await v.call<string[]>(FS.readdir, dir);
 
       for (let name of names) {
-        let path = Path.join(dir, name);
+        let path: string | undefined = Path.join(dir, name);
         let stats = await safeStat(path);
 
         if (stats!.isFile()) {
-          if (name === 'default.js' || Path.extname(path) !== '.js') {
+          const ext = Path.extname(path);
+          name = Path.basename(path).replace(ext, '');
+
+          if (
+            name === 'default' ||
+            (ext !== '.js' && ext !== '.ts') ||
+            path.endsWith('.d.ts')
+          ) {
             continue;
           }
-
-          name = Path.basename(name, '.js');
         } else {
-          path = Path.join(path, 'default.js');
-          stats = await safeStat(path);
+          path = await existsFile(path);
         }
 
         let existingItem = helpItemMap.get(name);
@@ -130,7 +135,7 @@ export class HelpInfo implements Printable {
         let commandConstructor: CommandClass | undefined;
         let brief: string | undefined;
 
-        if (stats) {
+        if (path) {
           let module = require(path) as CommandModule;
           commandConstructor = module.default;
           brief =
diff --git a/src/internal-util/fs.ts b/src/internal-util/fs.ts
index f045d03..f71f5bb 100644
--- a/src/internal-util/fs.ts
+++ b/src/internal-util/fs.ts
@@ -1,4 +1,5 @@
 import * as FS from 'fs';
+import * as Path from 'path';
 
 import * as v from 'villa';
 
@@ -6,9 +7,25 @@ export async function safeStat(path: string): Promise<FS.Stats | undefined> {
   return v.call(FS.stat, path).catch(v.bear);
 }
 
-export async function existsFile(path: string): Promise<boolean> {
-  let stats = await safeStat(path);
-  return !!stats && stats.isFile();
+export function existsFile(
+  path: string,
+  filename: string = 'default',
+): string | undefined {
+  const checkPaths = [Path.join(path, filename)];
+
+  if (filename === 'default') {
+    checkPaths.unshift(path);
+  }
+
+  for (const check of checkPaths) {
+    try {
+      return require.resolve(check);
+    } catch {
+      continue;
+    }
+  }
+
+  return undefined;
 }
 
 export async function existsDir(path: string): Promise<boolean> {