diff --git a/packages/cli/src/dev.ts b/packages/cli/src/dev.ts
new file mode 100644
index 0000000..26e85d4
--- /dev/null
+++ b/packages/cli/src/dev.ts
@@ -0,0 +1,87 @@
+import { createServer } from "vite";
+import { join } from "node:path";
+import { createLogger } from "./logger.ts";
+import { vueTuiDevPlugin } from "./vite-plugin.ts";
+import { extractBundle, type MemoryFiles } from "./bundle-extractor.ts";
+import { createProcessManager } from "./process-manager.ts";
+
+async function waitForBundle(env: { memoryFiles: MemoryFiles }): Promise<void> {
+  while (env.memoryFiles.files.size === 0) {
+    await new Promise((r) => setTimeout(r, 100));
+  }
+}
+
+export async function dev(entry?: string) {
+  const logger = createLogger();
+  logger.info("Starting vue-tui dev server...");
+
+  const server = await createServer({
+    plugins: [vueTuiDevPlugin({ entry })],
+  });
+
+  await server.listen();
+  const port = server.config.server.port!;
+  logger.info(`Vite dev server on port ${port}`);
+
+  const clientEnv = server.environments?.client as unknown as {
+    memoryFiles: MemoryFiles;
+  };
+
+  if (!clientEnv?.memoryFiles) {
+    logger.error("bundledDev environment not available. Ensure Vite 8+ with bundledDev support.");
+    process.exit(1);
+  }
+
+  logger.info("Waiting for initial bundle...");
+  await waitForBundle(clientEnv);
+
+  const outDir = join(process.cwd(), "node_modules", ".vue-tui", "dev");
+  let bundlePath = await extractBundle(clientEnv.memoryFiles, outDir);
+  logger.info("Bundle ready.");
+
+  let crashed = false;
+
+  const pm = createProcessManager({
+    bundlePath,
+    hmrPort: port,
+    logger,
+    onExit(code) {
+      if (code !== 0 && code !== null) {
+        crashed = true;
+        logger.info(`Process exited with code ${code}. Waiting for file changes...`);
+      }
+    },
+  });
+
+  pm.spawn();
+
+  // Listen for full reload requests from child
+  server.hot.on("vue-tui:request-reload", async () => {
+    const newPath = await extractBundle(clientEnv.memoryFiles, outDir);
+    pm.setBundlePath(newPath);
+    pm.restart();
+  });
+
+  // Re-spawn after crash on next successful bundle update
+  setInterval(async () => {
+    if (!crashed || pm.running) return;
+    try {
+      const newPath = await extractBundle(clientEnv.memoryFiles, outDir);
+      pm.setBundlePath(newPath);
+      crashed = false;
+      pm.spawn();
+    } catch {
+      // Build still broken, keep waiting
+    }
+  }, 500);
+
+  // Graceful shutdown
+  const shutdown = async () => {
+    await pm.shutdown();
+    await server.close();
+    process.exit(0);
+  };
+
+  process.on("SIGINT", shutdown);
+  process.on("SIGTERM", shutdown);
+}
diff --git a/packages/cli/src/index.ts b/packages/cli/src/index.ts
index 09dd62a..d33af26 100644
--- a/packages/cli/src/index.ts
+++ b/packages/cli/src/index.ts
@@ -1,4 +1,25 @@
 #!/usr/bin/env node
 
-const entry = process.argv[2];
-console.log(`vue-tui dev ${entry ?? "(auto-detect)"} — not yet implemented`);
+import { existsSync } from "node:fs";
+import { dev } from "./dev.ts";
+
+const args = process.argv.slice(2);
+const command = args[0];
+
+if (command !== "dev" && command !== undefined) {
+  console.error(`Unknown command: ${command}. Usage: vue-tui dev [entry]`);
+  process.exit(1);
+}
+
+const explicitEntry = args[1];
+
+function resolveEntry(): string | undefined {
+  if (explicitEntry) return explicitEntry;
+  const conventions = ["src/main.ts", "src/main.tsx", "src/index.ts", "src/index.tsx"];
+  return conventions.find((p) => existsSync(p));
+}
+
+dev(resolveEntry()).catch((err) => {
+  console.error(err);
+  process.exit(1);
+});