🔧
Gemini CLIをインストールしたらエラーになったので直す

2025/09/14に公開
 概要Gemini CLIはGoogleが提供するコマンドラインツールで、ターミナルから直接Gemini AIと対話できるツールです。Node.jsベースで作られており、今回はVoltaでパッケージバージョンを管理しつつインストールすることにしました。環境はWindows 11 + PowerShell 7です。
Gemini CLIをインストールする際にエラーに遭遇したので、対処方法についてメモを残しておきます。

 エラーの内容と対処方法
 エラー1: geminiコマンドが認識されない
 エラー内容Gemini CLIをインストール後、geminiコマンドを実行すると以下のエラーが発生しました。
gemini: The term 'gemini' is not recognized as a name of a cmdlet, function, script file, or executable program.
Check the spelling of the name, or if a path was included, verify that the path is correct and try again.

 原因このエラーは、Voltaがインストールしたツールへのパスが正しく設定されていないことが原因です。Voltaは初回セットアップ時に環境変数を設定しますが、場合によってはこの設定が完了していないことがあります。

 対処方法
volta setup を実行する
このコマンドはVoltaが必要な環境変数を再設定し、インストールしたツールへのパスが正しく通るようにしてくれるようです。実行後は新しいターミナルセッションを開くか、現在のセッションを再起動してください。

 エラー2: IDE拡張機能への接続エラーVS Codeを起動し、/ide でVS Codeと接続しようとしたタイミングで発生しました。
Debug Console

ℹ Loaded cached credentials.
ℹ Authenticated via "oauth-personal".
✖ [ERROR] [IDEClient] Failed to connect to IDE companion extension in VS Code. Please ensure the extension is running. To install the extension, run /ide install. (x2)
✖ [FileCommandLoader] Error loading commands from C:\Users\user\source\repos\tabi-nara-03\.gemini\commands: DOMException [AbortError]: This operation was aborted
       at new DOMException (node:internal/per_context/domexception:76:18)
       at AbortController.abort (node:internal/abort_controller:506:18)
       at file:///C:/Users/user/AppData/Local/Volta/tools/image/packages/@google/gemini-cli/node_modules/@google/gemini-cli/dist/src/ui/hooks/slashCommandProcessor.js:185:24
       at react-stack-bottom-frame(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:15957:13)
       at runWithFiberInDEV(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:1735:30)
       at commitHookEffectListUnmount(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:9607:17)
       at commitHookPassiveUnmountEffects(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:9654:11)
       at commitPassiveUnmountOnFiber(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11713:13)
       at recursivelyTraversePassiveUnmountEffects(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11703:11)
       at commitPassiveUnmountOnFiber(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11741:11)
✖ [ERROR] [IDEClient] Failed to connect to IDE companion extension in VS Code. Please ensure the extension is running. To install the extension, run /ide install.
✖ [FileCommandLoader] Error loading commands from C:\Users\user\source\repos\tabi-nara-03\.gemini\commands: DOMException [AbortError]: This operation was aborted
       at new DOMException (node:internal/per_context/domexception:76:18)
       at AbortController.abort (node:internal/abort_controller:506:18)
       at file:///C:/Users/user/AppData/Local/Volta/tools/image/packages/@google/gemini-cli/node_modules/@google/gemini-cli/dist/src/ui/hooks/slashCommandProcessor.js:185:24
       at react-stack-bottom-frame(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:15957:13)
       at runWithFiberInDEV(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:1735:30)
       at commitHookEffectListUnmount(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:9607:17)
       at commitHookPassiveUnmountEffects(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:9654:11)
       at commitPassiveUnmountOnFiber(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11713:13)
       at recursivelyTraversePassiveUnmountEffects(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11703:11)
       at commitPassiveUnmountOnFiber(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11741:11)
✖ [ERROR] [IDEClient] Failed to connect to IDE companion extension in VS Code. Please ensure the extension is running. To install the extension, run /ide install.
✖ [FileCommandLoader] Error loading commands from C:\Users\user\source\repos\tabi-nara-03\.gemini\commands: DOMException [AbortError]: This operation was aborted
       at new DOMException (node:internal/per_context/domexception:76:18)
       at AbortController.abort (node:internal/abort_controller:506:18)
       at file:///C:/Users/user/AppData/Local/Volta/tools/image/packages/@google/gemini-cli/node_modules/@google/gemini-cli/dist/src/ui/hooks/slashCommandProcessor.js:185:24
       at react-stack-bottom-frame(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:15957:13)
       at runWithFiberInDEV(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:1735:30)
       at commitHookEffectListUnmount(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:9607:17)
       at commitHookPassiveUnmountEffects(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:9654:11)
       at commitPassiveUnmountOnFiber(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11713:13)
       at recursivelyTraversePassiveUnmountEffects(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11703:11)
       at commitPassiveUnmountOnFiber(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11741:11)
✖ [ERROR] [IDEClient] Failed to connect to IDE companion extension in VS Code. Please ensure the extension is running. To install the extension, run /ide install.
✖ [FileCommandLoader] Error loading commands from C:\Users\user\source\repos\tabi-nara-03\.gemini\commands: DOMException [AbortError]: This operation was aborted
       at new DOMException (node:internal/per_context/domexception:76:18)
       at AbortController.abort (node:internal/abort_controller:506:18)
       at file:///C:/Users/user/AppData/Local/Volta/tools/image/packages/@google/gemini-cli/node_modules/@google/gemini-cli/dist/src/ui/hooks/slashCommandProcessor.js:185:24
       at react-stack-bottom-frame(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:15957:13)
       at runWithFiberInDEV(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\
   gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:1735:30)
       at commitHookEffectListUnmount(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:9607:17)
       at commitHookPassiveUnmountEffects(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:9654:11)
       at commitPassiveUnmountOnFiber(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11713:13)
       at recursivelyTraversePassiveUnmountEffects(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11703:11)
       at commitPassiveUnmountOnFiber(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11741:11)
✖ [ERROR] [IDEClient] Failed to connect to IDE companion extension in VS Code. Please ensure the extension is running. To install the extension, run /ide install.
✖ [FileCommandLoader] Error loading commands from C:\Users\user\source\repos\tabi-nara-03\.gemini\commands: DOMException [AbortError]: This operation was aborted
       at new DOMException (node:internal/per_context/domexception:76:18)
       at AbortController.abort (node:internal/abort_controller:506:18)
       at file:///C:/Users/user/AppData/Local/Volta/tools/image/packages/@google/gemini-cli/node_modules/@google/gemini-cli/dist/src/ui/hooks/slashCommandProcessor.js:185:24
       at react-stack-bottom-frame(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:15957:13)
       at runWithFiberInDEV(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:1735:30)
       at commitHookEffectListUnmount(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:9607:17)
       at commitHookPassiveUnmountEffects(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:9654:11)
       at commitPassiveUnmountOnFiber(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11713:13)
       at recursivelyTraversePassiveUnmountEffects(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11703:11)
       at commitPassiveUnmountOnFiber(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11741:11)
✖ [ERROR] [IDEClient] Failed to connect to IDE companion extension in VS Code. Please ensure the extension is running. To install the extension, run /ide install.
✖ [FileCommandLoader] Error loading commands from C:\Users\user\source\repos\tabi-nara-03\.gemini\commands: DOMException [AbortError]: This operation was aborted
       at new DOMException (node:internal/per_context/domexception:76:18)
       at AbortController.abort (node:internal/abort_controller:506:18)
       at file:///C:/Users/user/AppData/Local/Volta/tools/image/packages/@google/gemini-cli/node_modules/@google/gemini-cli/dist/src/ui/hooks/slashCommandProcessor.js:185:24
       at react-stack-bottom-frame(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:15957:13)
       at runWithFiberInDEV(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:1735:30)
       at commitHookEffectListUnmount(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:9607:17)
       at commitHookPassiveUnmountEffects(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:9654:11)
       at commitPassiveUnmountOnFiber(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11713:13)
       at recursivelyTraversePassiveUnmountEffects(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11703:11)
       at commitPassiveUnmountOnFiber(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11741:11)
✖ [ERROR] [IDEClient] Failed to connect to IDE companion extension in VS Code. Please ensure the extension is running. To install the extension, run /ide install.
✖ [FileCommandLoader] Error loading commands from C:\Users\user\source\repos\tabi-nara-03\.gemini\commands: DOMException [AbortError]: This operation was aborted
       at new DOMException (node:internal/per_context/domexception:76:18)
       at AbortController.abort (node:internal/abort_controller:506:18)
       at file:///C:/Users/user/AppData/Local/Volta/tools/image/packages/@google/gemini-cli/node_modules/@google/gemini-cli/dist/src/ui/hooks/slashCommandProcessor.js:185:24
       at react-stack-bottom-frame(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:15957:13)
       at runWithFiberInDEV(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:1735:30)
       at commitHookEffectListUnmount(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:9607:17)
       at commitHookPassiveUnmountEffects(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:9654:11)
       at commitPassiveUnmountOnFiber(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11713:13)
       at recursivelyTraversePassiveUnmountEffects(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11703:11)
       at commitPassiveUnmountOnFiber(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11741:11)
✖ [ERROR] [IDEClient] Failed to connect to IDE companion extension in VS Code. Please ensure the extension is running. To install the extension, run /ide install.
✖ [FileCommandLoader] Error loading commands from C:\Users\user\source\repos\tabi-nara-03\.gemini\commands: DOMException [AbortError]: This operation was aborted
       at new DOMException (node:internal/per_context/domexception:76:18)
       at AbortController.abort (node:internal/abort_controller:506:18)
       at file:///C:/Users/user/AppData/Local/Volta/tools/image/packages/@google/gemini-cli/node_modules/@google/gemini-cli/dist/src/ui/hooks/slashCommandProcessor.js:185:24
       at react-stack-bottom-frame(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:15957:13)
       at runWithFiberInDEV(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:1735:30)
       at commitHookEffectListUnmount(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:9607:17)
       at commitHookPassiveUnmountEffects(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:9654:11)
       at commitPassiveUnmountOnFiber(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11713:13)
       at recursivelyTraversePassiveUnmountEffects(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11703:11)
       at commitPassiveUnmountOnFiber(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11741:11)
✖ [ERROR] [IDEClient] Failed to connect to IDE companion extension in VS Code. Please ensure the extension is running. To install the extension, run /ide install.
✖ [FileCommandLoader] Error loading commands from C:\Users\user\source\repos\tabi-nara-03\.gemini\commands: DOMException [AbortError]: This operation was aborted
       at new DOMException (node:internal/per_context/domexception:76:18)
       at AbortController.abort (node:internal/abort_controller:506:18)
       at file:///C:/Users/user/AppData/Local/Volta/tools/image/packages/@google/gemini-cli/node_modules/@google/gemini-cli/dist/src/ui/hooks/slashCommandProcessor.js:185:24
       at react-stack-bottom-frame(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:15957:13)
       at runWithFiberInDEV(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:1735:30)
       at commitHookEffectListUnmount(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:9607:17)
       at commitHookPassiveUnmountEffects(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:9654:11)
       at commitPassiveUnmountOnFiber(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11713:13)
       at recursivelyTraversePassiveUnmountEffects(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11703:11)
       at commitPassiveUnmountOnFiber(C:\Users\user\AppData\Local\Volta\tools\image\packages\@google\gemini-cli\node_modules\@google\gemini-cli\node_modules\react-reconciler\cjs\react-reconciler.development.js:11741:11)

 エラー内容主なエラーメッセージは「Failed to connect to IDE companion extension in VS Code」です。

 原因専用の拡張機能「Gemini CLI Companion」が必要です。この拡張機能がインストールされていない、または正しく起動していない場合にこのエラーが発生するようです。

 対処方法VSCodeで拡張機能タブを開く（Ctrl+Shift+X）
"Gemini CLI Companion" (Google.gemini-cli-vscode-ide-companion) をインストール
VSCodeを再起動 (もしかしたらターミナルの再起動でも直るかもしれない)
拡張機能をインストールして再起動することで、Gemini CLIとVS Codeが正常に連携できるようになり、エラーが解消されます。

 おまけ（回避方法）Claude Codeに質問すると npx @google/gemini-cli による都度実行をお勧めされました。この方法ならVoltaのセットアップなしですぐに使えるメリットがありますが、今回はVoltaでのグローバルインストールにこだわって対処しました。

 まとめGemini CLIのインストール時に遭遇したエラーは、いずれも環境設定に関するものでした。最初のエラーはVoltaのパス設定、2つ目のエラーはVS Code拡張機能の不足が原因でした。
これらのエラーは比較的よく出るエラーのようです。

なんとかエラーも解消して、ようやくスタート地点に立つことができました。
GitHubで編集を提案
概要

エラーの内容と対処方法

エラー1: geminiコマンドが認識されない

エラー内容

原因

対処方法

エラー2: IDE拡張機能への接続エラー

エラー内容

原因

対処方法

おまけ（回避方法）

まとめ

Discussion
