diff --git a/package.json b/package.json
new file mode 100644
index 0000000..9746460
--- /dev/null
+++ b/package.json
@@ -0,0 +1,17 @@
+{
+  "name": "as-test-flight-sim",
+  "version": "0.1.0",
+  "private": true,
+  "description": "Offline Cesium aircraft maneuver planning prototype with a local simulation service.",
+  "scripts": {
+    "dev": "node tools/dev.mjs",
+    "service": "node service/src/server.js",
+    "test:service": "node service/src/simulator.test.js",
+    "web:dev": "npm --prefix web-test run dev",
+    "web:build": "npm --prefix web-test run build",
+    "copy:cesium": "node tools/copy-cesium-assets.mjs"
+  },
+  "engines": {
+    "node": ">=20"
+  }
+}
diff --git a/tools/copy-cesium-assets.mjs b/tools/copy-cesium-assets.mjs
new file mode 100644
index 0000000..1d2ef24
--- /dev/null
+++ b/tools/copy-cesium-assets.mjs
@@ -0,0 +1,26 @@
+import { cpSync, existsSync, mkdirSync, rmSync } from "node:fs";
+import { dirname, join } from "node:path";
+import { fileURLToPath } from "node:url";
+
+const root = dirname(dirname(fileURLToPath(import.meta.url)));
+const candidateBuilds = [
+  join(root, "node_modules", "cesium", "Build", "Cesium"),
+  join(root, "web-test", "node_modules", "cesium", "Build", "Cesium"),
+];
+const cesiumBuild = candidateBuilds.find((value) => existsSync(value));
+const target = join(root, "web-test", "public", "cesium");
+
+if (!cesiumBuild) {
+  throw new Error("Cesium package is not installed. Run npm.cmd install first.");
+}
+
+mkdirSync(target, { recursive: true });
+
+for (const name of ["Assets", "ThirdParty", "Workers", "Widgets"]) {
+  const source = join(cesiumBuild, name);
+  const destination = join(target, name);
+  rmSync(destination, { recursive: true, force: true });
+  cpSync(source, destination, { recursive: true });
+}
+
+console.log(`Copied Cesium runtime assets to ${target}`);
diff --git a/tools/dev.mjs b/tools/dev.mjs
new file mode 100644
index 0000000..73c8115
--- /dev/null
+++ b/tools/dev.mjs
@@ -0,0 +1,78 @@
+import { spawn } from "node:child_process";
+import net from "node:net";
+
+const commands = [
+  {
+    name: "service",
+    command: "node",
+    args: ["service/src/server.js"],
+    port: 4317
+  },
+  {
+    name: "web",
+    command: "npm.cmd",
+    args: ["run", "web:dev"],
+    port: 5173
+  }
+];
+
+const occupied = [];
+for (const command of commands) {
+  if (await isPortInUse(command.port)) {
+    occupied.push(command);
+  }
+}
+
+if (occupied.length > 0) {
+  for (const command of occupied) {
+    console.error(`[dev] port ${command.port} is already in use; not starting ${command.name}.`);
+  }
+  console.error("[dev] stop the old process first, then run npm.cmd run dev again.");
+  process.exit(1);
+}
+
+const children = commands.map(({ name, command, args }) => {
+  const child = spawn(command, args, {
+    cwd: process.cwd(),
+    stdio: ["ignore", "pipe", "pipe"],
+    shell: false
+  });
+
+  child.stdout.on("data", (data) => writePrefixed(name, data));
+  child.stderr.on("data", (data) => writePrefixed(name, data));
+  child.on("exit", (code) => {
+    if (code !== 0 && code !== null) {
+      console.error(`[${name}] exited with code ${code}`);
+    }
+  });
+
+  return child;
+});
+
+for (const signal of ["SIGINT", "SIGTERM"]) {
+  process.on(signal, () => {
+    for (const child of children) {
+      child.kill(signal);
+    }
+    process.exit(0);
+  });
+}
+
+function writePrefixed(name, data) {
+  const lines = data.toString().split(/\r?\n/).filter(Boolean);
+  for (const line of lines) {
+    console.log(`[${name}] ${line}`);
+  }
+}
+
+function isPortInUse(port) {
+  return new Promise((resolve) => {
+    const server = net.createServer();
+
+    server.once("error", () => resolve(true));
+    server.once("listening", () => {
+      server.close(() => resolve(false));
+    });
+    server.listen(port, "127.0.0.1");
+  });
+}