diff --git a/build.ts b/build.ts
index 927952589..6cffa52b1 100644
--- a/build.ts
+++ b/build.ts
@@ -172,3 +172,40 @@ chmodSync(cliBun, 0o755)
 chmodSync(cliNode, 0o755)
 
 console.log(`Generated ${cliBun} (shebang: bun) and ${cliNode} (shebang: node)`)
+
+// Step 7: Compile standalone executable (csc.exe on Windows, csc on Unix)
+// Must use Bun.build({ compile: true, features }) instead of `bun build --compile`
+// because the CLI command doesn't support the --feature flag.
+// NOTE: compile mode uses outdir (not outfile) — Bun names the output after the entrypoint.
+const isWin = process.platform === 'win32'
+const exeName = isWin ? 'csc.exe' : 'csc'
+
+const compileResult = await Bun.build({
+  entrypoints: ['src/entrypoints/cli.tsx'],
+  target: 'bun',
+  compile: true,
+  define: getMacroDefines(),
+  features,
+  outdir: import.meta.dir,
+})
+
+if (!compileResult.success) {
+  console.error('Compile failed:')
+  for (const log of compileResult.logs) {
+    console.error(log)
+  }
+  process.exit(1)
+}
+
+// Rename auto-generated cli.tsx.exe → csc.exe
+const generated = compileResult.outputs[0]
+const targetPath = join(import.meta.dir, exeName)
+if (generated && generated.path !== targetPath) {
+  const { renameSync, unlinkSync, existsSync } = await import('fs')
+  if (existsSync(targetPath)) {
+    try { unlinkSync(targetPath) } catch { /* locked by running process */ }
+  }
+  renameSync(generated.path, targetPath)
+}
+
+console.log(`Compiled standalone executable: ${join(import.meta.dir, exeName)}`)
diff --git a/src/server/childSpawn.ts b/src/server/childSpawn.ts
index f4cc8cb1c..9ef52e639 100644
--- a/src/server/childSpawn.ts
+++ b/src/server/childSpawn.ts
@@ -6,6 +6,10 @@ export const INIT_TIMEOUT_MS = (() => {
 export function getScriptArgsForChild(): string[] {
   const argv1 = process.argv[1]
   if (!argv1) return []
+  // Bun standalone executable embeds a virtual snapshot path like "B:/~BUN/root/cli.js".
+  // This is not a real file on disk — skip it so the child process (the same exe)
+  // is not launched with a bogus script argument.
+  if (argv1.startsWith('B:/~BUN/') || argv1.startsWith('/snapshot/')) return []
   if (argv1.endsWith('.ts') || argv1.endsWith('.tsx') || argv1.includes('/') || argv1.includes('\\')) {
     return [argv1]
   }
@@ -23,19 +27,26 @@ export async function saveChildSpawnPrefix(): Promise<void> {
   const { execPath, scriptArgs } = getChildSpawnArgs()
   let defineArgs: string[] = []
   let featureArgs: string[] = []
-  try {
-    const definesMod = await import('../../scripts/defines.js') as { getMacroDefines: () => Record<string, string>; DEFAULT_BUILD_FEATURES: readonly string[] }
-    const defines = definesMod.getMacroDefines()
-    defineArgs = Object.entries(defines).flatMap(([k, v]) => ['-d', `${k}:${v}`])
-    const features = definesMod.DEFAULT_BUILD_FEATURES
-    featureArgs = features.flatMap((f: string) => ['--feature', f])
-  } catch {}
-  const envFeatures = Object.entries(process.env)
-    .filter(([k]) => k.startsWith('FEATURE_') && k.slice(8))
-    .map(([k]) => ['--feature', k.slice(8)] as [string, string])
-    .flat()
-  const allFeatureArgs = [...featureArgs, ...envFeatures]
-  const prefix = JSON.stringify({ execPath, scriptArgs, defineArgs, featureArgs: allFeatureArgs })
+  // Only pass --feature/define flags when running as a script (dev mode).
+  // In compiled standalone executable mode scriptArgs is empty, and feature
+  // flags are already baked in at compile time — passing --feature to the
+  // child process would cause "unknown option" errors.
+  const isScriptMode = scriptArgs.length > 0
+  if (isScriptMode) {
+    try {
+      const definesMod = await import('../../scripts/defines.js') as { getMacroDefines: () => Record<string, string>; DEFAULT_BUILD_FEATURES: readonly string[] }
+      const defines = definesMod.getMacroDefines()
+      defineArgs = Object.entries(defines).flatMap(([k, v]) => ['-d', `${k}:${v}`])
+      const features = definesMod.DEFAULT_BUILD_FEATURES
+      featureArgs = features.flatMap((f: string) => ['--feature', f])
+    } catch {}
+    const envFeatures = Object.entries(process.env)
+      .filter(([k]) => k.startsWith('FEATURE_') && k.slice(8))
+      .map(([k]) => ['--feature', k.slice(8)] as [string, string])
+      .flat()
+    featureArgs = [...featureArgs, ...envFeatures]
+  }
+  const prefix = JSON.stringify({ execPath, scriptArgs, defineArgs, featureArgs })
   process.env._CSC_CHILD_SPAWN_PREFIX = prefix
 }