feat: add --js-runtime option to use bun instead of node

src/claude/claudeRemote.ts

@@ -10,6 +10,7 @@ import { getProjectPath } from "./utils/path";
 import { awaitFileExist } from "@/modules/watcher/awaitFileExist";
 import { systemPrompt } from "./utils/systemPrompt";
 import { PermissionResult } from "./sdk/types";
+import type { JsRuntime } from "./runClaude";
 
 export async function claudeRemote(opts: {
 
@@ -24,6 +25,8 @@ export async function claudeRemote(opts: {
     canCallTool: (toolName: string, input: unknown, mode: EnhancedMode, options: { signal: AbortSignal }) => Promise<PermissionResult>,
     /** Path to temporary settings file with SessionStart hook (required for session tracking) */
     hookSettingsPath: string,
+    /** JavaScript runtime to use for spawning Claude Code (default: 'node') */
+    jsRuntime?: JsRuntime,
 
     // Dynamic parameters
     nextMessage: () => Promise<{ message: string, mode: EnhancedMode } | null>,
@@ -121,7 +124,7 @@ export async function claudeRemote(opts: {
         allowedTools: initial.mode.allowedTools ? initial.mode.allowedTools.concat(opts.allowedTools) : opts.allowedTools,
         disallowedTools: initial.mode.disallowedTools,
         canCallTool: (toolName: string, input: unknown, options: { signal: AbortSignal }) => opts.canCallTool(toolName, input, mode, options),
-        executable: 'node',
+        executable: opts.jsRuntime ?? 'node',
         abort: opts.signal,
         pathToClaudeCodeExecutable: (() => {
             return resolve(join(projectPath(), 'scripts', 'claude_remote_launcher.cjs'));

src/claude/claudeRemoteLauncher.ts

@@ -330,6 +330,7 @@ export async function claudeRemoteLauncher(session: Session): Promise<'switch' |
                     allowedTools: session.allowedTools ?? [],
                     mcpServers: session.mcpServers,
                     hookSettingsPath: session.hookSettingsPath,
+                    jsRuntime: session.jsRuntime,
                     canCallTool: permissionHandler.handleToolCall,
                     isAborted: (toolCallId: string) => {
                         return permissionHandler.isAborted(toolCallId);

src/claude/loop.ts

@@ -5,6 +5,7 @@ import { Session } from "./session"
 import { claudeLocalLauncher } from "./claudeLocalLauncher"
 import { claudeRemoteLauncher } from "./claudeRemoteLauncher"
 import { ApiClient } from "@/lib"
+import type { JsRuntime } from "./runClaude"
 
 export type PermissionMode = 'default' | 'acceptEdits' | 'bypassPermissions' | 'plan';
 
@@ -34,6 +35,8 @@ interface LoopOptions {
     onSessionReady?: (session: Session) => void
     /** Path to temporary settings file with SessionStart hook (required for session tracking) */
     hookSettingsPath: string
+    /** JavaScript runtime to use for spawning Claude Code (default: 'node') */
+    jsRuntime?: JsRuntime
 }
 
 export async function loop(opts: LoopOptions) {
@@ -52,7 +55,8 @@ export async function loop(opts: LoopOptions) {
         messageQueue: opts.messageQueue,
         allowedTools: opts.allowedTools,
         onModeChange: opts.onModeChange,
-        hookSettingsPath: opts.hookSettingsPath
+        hookSettingsPath: opts.hookSettingsPath,
+        jsRuntime: opts.jsRuntime
     });
 
     // Notify that session is ready

src/claude/runClaude.ts

@@ -25,6 +25,9 @@ import { projectPath } from '../projectPath';
 import { resolve } from 'node:path';
 import { Session } from './session';
 
+/** JavaScript runtime to use for spawning Claude Code */
+export type JsRuntime = 'node' | 'bun'
+
 export interface StartOptions {
     model?: string
     permissionMode?: 'default' | 'acceptEdits' | 'bypassPermissions' | 'plan'
@@ -33,6 +36,8 @@ export interface StartOptions {
     claudeEnvVars?: Record<string, string>
     claudeArgs?: string[]
     startedBy?: 'daemon' | 'terminal'
+    /** JavaScript runtime to use for spawning Claude Code (default: 'node') */
+    jsRuntime?: JsRuntime
 }
 
 export async function runClaude(credentials: Credentials, options: StartOptions = {}): Promise<void> {
@@ -405,7 +410,8 @@ export async function runClaude(credentials: Credentials, options: StartOptions
         session,
         claudeEnvVars: options.claudeEnvVars,
         claudeArgs: options.claudeArgs,
-        hookSettingsPath
+        hookSettingsPath,
+        jsRuntime: options.jsRuntime
     });
 
     // Send session death message

src/claude/session.ts

@@ -2,6 +2,7 @@ import { ApiClient, ApiSessionClient } from "@/lib";
 import { MessageQueue2 } from "@/utils/MessageQueue2";
 import { EnhancedMode } from "./loop";
 import { logger } from "@/ui/logger";
+import type { JsRuntime } from "./runClaude";
 
 export class Session {
     readonly path: string;
@@ -16,6 +17,8 @@ export class Session {
     readonly _onModeChange: (mode: 'local' | 'remote') => void;
     /** Path to temporary settings file with SessionStart hook (required for session tracking) */
     readonly hookSettingsPath: string;
+    /** JavaScript runtime to use for spawning Claude Code (default: 'node') */
+    readonly jsRuntime: JsRuntime;
 
     sessionId: string | null;
     mode: 'local' | 'remote' = 'local';
@@ -41,6 +44,8 @@ export class Session {
         allowedTools?: string[],
         /** Path to temporary settings file with SessionStart hook (required for session tracking) */
         hookSettingsPath: string,
+        /** JavaScript runtime to use for spawning Claude Code (default: 'node') */
+        jsRuntime?: JsRuntime,
     }) {
         this.path = opts.path;
         this.api = opts.api;
@@ -54,6 +59,7 @@ export class Session {
         this.allowedTools = opts.allowedTools;
         this._onModeChange = opts.onModeChange;
         this.hookSettingsPath = opts.hookSettingsPath;
+        this.jsRuntime = opts.jsRuntime ?? 'node';
 
         // Start keep alive
         this.client.keepAlive(this.thinking, this.mode);

src/index.ts

@@ -406,6 +406,13 @@ ${chalk.bold('To clean up runaway processes:')} Use ${chalk.cyan('happy doctor c
         unknownArgs.push('--dangerously-skip-permissions')
       } else if (arg === '--started-by') {
         options.startedBy = args[++i] as 'daemon' | 'terminal'
+      } else if (arg === '--js-runtime') {
+        const runtime = args[++i]
+        if (runtime !== 'node' && runtime !== 'bun') {
+          console.error(chalk.red(`Invalid --js-runtime value: ${runtime}. Must be 'node' or 'bun'`))
+          process.exit(1)
+        }
+        options.jsRuntime = runtime
       } else if (arg === '--claude-env') {
         // Parse KEY=VALUE environment variable to pass to Claude
         const envArg = args[++i]
@@ -454,6 +461,7 @@ ${chalk.bold('Examples:')}
   happy                    Start session
   happy --yolo             Start with bypassing permissions
                             happy sugar for --dangerously-skip-permissions
+  happy --js-runtime bun   Use bun instead of node to spawn Claude Code
   happy --claude-env ANTHROPIC_BASE_URL=http://127.0.0.1:3456
                            Use a custom API endpoint (e.g., claude-code-router)
   happy auth login --force Authenticate