diff --git a/cli/scripts/build-cli.js b/cli/scripts/build-cli.js
index 3af3120f..d4e4d279 100644
--- a/cli/scripts/build-cli.js
+++ b/cli/scripts/build-cli.js
@@ -81,205 +81,272 @@ function copyRecursive(src, dest) {
   }
 }
 
-console.log("📦 Building 9Router CLI package with Next.js...\n");
+function resolveStandaloneBuild(appDir, buildDistDir) {
+  const legacyStandaloneRoot = path.join(appDir, ".next", "standalone");
+  const resolvedStandaloneRoot = path.join(buildDistDir, "standalone");
+  let standaloneRoot = fs.existsSync(resolvedStandaloneRoot)
+    ? resolvedStandaloneRoot
+    : legacyStandaloneRoot;
 
-fs.mkdirSync(buildHomeDir, { recursive: true });
-fs.mkdirSync(path.join(buildHomeDir, "AppData", "Roaming"), { recursive: true });
-fs.mkdirSync(path.join(buildHomeDir, "AppData", "Local"), { recursive: true });
-
-// Step 0: Sync version from app/cli/package.json to app/package.json
-console.log("0️⃣  Syncing version to app/package.json...");
-const cliPkg = JSON.parse(fs.readFileSync(path.join(cliDir, "package.json"), "utf8"));
-const appPkgPath = path.join(appDir, "package.json");
-const appPkg = JSON.parse(fs.readFileSync(appPkgPath, "utf8"));
-if (appPkg.version !== cliPkg.version) {
-  appPkg.version = cliPkg.version;
-  fs.writeFileSync(appPkgPath, JSON.stringify(appPkg, null, 2) + "\n");
-  console.log(`✅ Version synced: ${cliPkg.version}\n`);
-} else {
-  console.log(`✅ Version already synced: ${cliPkg.version}\n`);
-}
-
-// Step 1: Build app with Next.js (workspace tracing root → traced node_modules in standalone).
-console.log("1️⃣  Building Next.js app...");
-try {
-  execSync("npm run build", {
-    stdio: "inherit",
-    cwd: appDir,
-    env: {
-      ...process.env,
-      HOME: buildHomeDir,
-      USERPROFILE: buildHomeDir,
-      APPDATA: path.join(buildHomeDir, "AppData", "Roaming"),
-      LOCALAPPDATA: path.join(buildHomeDir, "AppData", "Local"),
-      NEXT_DIST_DIR: buildDistDirName,
-      NEXT_TRACING_ROOT_MODE: "workspace",
-    }
-  });
-  console.log("✅ Next.js build completed\n");
-} catch (error) {
-  console.error("❌ Next.js build failed");
-  process.exit(1);
-}
-
-// Step 2: Clean old app/cli/app if exists
-console.log("2️⃣  Cleaning old app/cli/app...");
-if (fs.existsSync(cliAppDir)) {
-  fs.rmSync(cliAppDir, { recursive: true, force: true });
-}
-console.log("✅ Cleaned\n");
-
-// Step 3: Copy Next.js standalone build to app/cli/app.
-// Newer Next.js standalone output writes server.js/package.json plus .next/, src/, and
-// node_modules/ directly under .next/standalone. Older builds may still use a nested app/.
-console.log("3️⃣  Copying Next.js standalone build to app/cli/app...");
-const standaloneRoot = path.join(appDir, ".next", "standalone");
-const standaloneRootResolved = path.join(buildDistDir, "standalone");
-let standaloneRootToUse = fs.existsSync(standaloneRootResolved) ? standaloneRootResolved : standaloneRoot;
-// Next.js 16 nests standalone output under the project name when NEXT_TRACING_ROOT_MODE=workspace
-// e.g. .next-cli-build/standalone/9router/server.js
-const pkgName = path.basename(appDir);
-const nestedRoot = path.join(standaloneRootToUse, pkgName);
-if (fs.existsSync(path.join(nestedRoot, "server.js")) && !fs.existsSync(path.join(standaloneRootToUse, "server.js"))) {
-  console.log(`ℹ️  Detected nested standalone output: ${pkgName}/`);
-  standaloneRootToUse = nestedRoot;
-}
-const standaloneApp = fs.existsSync(path.join(standaloneRootToUse, "server.js"))
-  ? standaloneRootToUse
-  : path.join(standaloneRootToUse, "app");
-if (!fs.existsSync(standaloneApp)) {
-  console.error("❌ Next.js standalone build not found under .next/standalone");
-  console.error("Expected either .next/standalone/server.js or .next/standalone/app/");
-  process.exit(1);
-}
-copyRecursive(standaloneApp, cliAppDir);
-
-// Older nested-app layout stores traced node_modules at standalone root.
-const standaloneNodeModules = path.join(standaloneRootToUse, "node_modules");
-if (standaloneApp !== standaloneRootToUse && fs.existsSync(standaloneNodeModules)) {
-  copyRecursive(standaloneNodeModules, path.join(cliAppDir, "node_modules"));
-}
-console.log("✅ Copied standalone build\n");
-
-// Step 3a: Copy custom server (injects real socket IP, strips spoofable XFF).
-const customServerSrc = path.join(appDir, "custom-server.js");
-if (fs.existsSync(customServerSrc)) {
-  fs.copyFileSync(customServerSrc, path.join(cliAppDir, "custom-server.js"));
-  console.log("✅ Copied custom-server.js\n");
-} else {
-  console.warn("⚠️  custom-server.js not found — server will run without real-IP injection\n");
-}
-
-// Step 3b: Ensure sql.js (pure JS fallback) bundled in app/cli/app/node_modules.
-// Strip better-sqlite3 (native) — it lives in ~/.9router/runtime to avoid
-// Windows EBUSY during global CLI updates. node:sqlite (Node ≥22.5) is also
-// available as a no-install middle tier.
-console.log("3️⃣ b Configuring SQLite drivers...");
-function ensureModuleInBundle(pkg) {
-  const dest = path.join(cliAppDir, "node_modules", pkg);
-  if (fs.existsSync(dest)) {
-    console.log(`✅ ${pkg} already bundled`);
-    return;
+  // Next.js 16 nests standalone output under the project name when
+  // NEXT_TRACING_ROOT_MODE=workspace, e.g. standalone/9router/server.js.
+  const pkgName = path.basename(appDir);
+  const nestedRoot = path.join(standaloneRoot, pkgName);
+  if (fs.existsSync(path.join(nestedRoot, "server.js")) && !fs.existsSync(path.join(standaloneRoot, "server.js"))) {
+    console.log(`ℹ️  Detected nested standalone output: ${pkgName}/`);
+    standaloneRoot = nestedRoot;
   }
-  const candidates = [
-    path.join(appDir, "node_modules", pkg),
-    path.join(rootDir, "node_modules", pkg),
+
+  const standaloneApp = fs.existsSync(path.join(standaloneRoot, "server.js"))
+    ? standaloneRoot
+    : path.join(standaloneRoot, "app");
+  if (!fs.existsSync(standaloneApp)) {
+    throw new Error(
+      "Next.js standalone build not found under .next/standalone; " +
+      "expected either .next/standalone/server.js or .next/standalone/app/",
+    );
+  }
+
+  return { standaloneApp, standaloneRoot };
+}
+
+function copyStandaloneBuild(appDir, buildDistDir, cliAppDir) {
+  const { standaloneApp, standaloneRoot } = resolveStandaloneBuild(appDir, buildDistDir);
+  copyRecursive(standaloneApp, cliAppDir);
+
+  // Older nested-app layout stores traced node_modules at standalone root.
+  const standaloneNodeModules = path.join(standaloneRoot, "node_modules");
+  if (standaloneApp !== standaloneRoot && fs.existsSync(standaloneNodeModules)) {
+    copyRecursive(standaloneNodeModules, path.join(cliAppDir, "node_modules"));
+  }
+}
+
+function mergeServerArtifacts(buildDistDir, cliAppDir) {
+  const serverSrc = path.join(buildDistDir, "server");
+  const serverDest = path.join(cliAppDir, buildDistDirName, "server");
+  if (!fs.existsSync(serverSrc)) {
+    throw new Error(`Complete Next.js server build not found: ${serverSrc}`);
+  }
+  copyRecursive(serverSrc, serverDest);
+}
+
+function assertRequiredApiArtifacts(cliAppDir) {
+  const requiredArtifacts = [
+    "app/api/v1/chat/completions/route.js",
+    "app/api/v1/messages/route.js",
   ];
-  const src = candidates.find((p) => fs.existsSync(p));
-  if (!src) {
-    console.warn(`⚠️  ${pkg} not found locally — bundle will rely on node:sqlite or runtime install`);
-    return;
+  const serverDir = path.join(cliAppDir, buildDistDirName, "server");
+  const missingArtifacts = requiredArtifacts
+    .map((artifact) => path.join(serverDir, artifact))
+    .filter((artifact) => !fs.existsSync(artifact));
+
+  if (missingArtifacts.length > 0) {
+    throw new Error(
+      `Required CLI API route artifact${missingArtifacts.length === 1 ? " is" : "s are"} missing:\n` +
+      missingArtifacts.join("\n"),
+    );
   }
-  fs.mkdirSync(path.dirname(dest), { recursive: true });
-  copyRecursive(src, dest);
-  console.log(`✅ Bundled ${pkg}`);
-}
-ensureModuleInBundle("sql.js");
-// `open` is external (see serverExternalPackages in next.config.mjs), so it must exist in
-// the bundle's node_modules or every importer throws MODULE_NOT_FOUND at runtime. Output
-// tracing normally copies it; this is the same belt-and-braces guard used for sql.js.
-ensureModuleInBundle("open");
-const betterDir = path.join(cliAppDir, "node_modules", "better-sqlite3");
-if (fs.existsSync(betterDir)) {
-  fs.rmSync(betterDir, { recursive: true, force: true });
-  console.log("✅ Stripped better-sqlite3 (lives in ~/.9router/runtime)");
-}
-console.log("");
-
-// Step 4: Copy static files
-console.log("4️⃣  Copying static files...");
-const staticSrc = path.join(appDir, ".next", "static");
-const staticSrcResolved = path.join(buildDistDir, "static");
-const staticDest = path.join(cliAppDir, buildDistDirName, "static");
-if (fs.existsSync(staticSrcResolved) || fs.existsSync(staticSrc)) {
-  copyRecursive(fs.existsSync(staticSrcResolved) ? staticSrcResolved : staticSrc, staticDest);
-  console.log("✅ Copied static files\n");
-} else {
-  console.log("⏭️  No static files found\n");
 }
 
-// Step 5: Copy public folder if exists
-console.log("5️⃣  Copying public folder...");
-const publicSrc = path.join(appDir, "public");
-const publicDest = path.join(cliAppDir, "public");
-if (fs.existsSync(publicSrc)) {
-  copyRecursive(publicSrc, publicDest);
-  console.log("✅ Copied public folder\n");
-} else {
-  console.log("⏭️  No public folder found\n");
+function buildCliPackage() {
+  console.log("📦 Building 9Router CLI package with Next.js...\n");
+
+  fs.mkdirSync(buildHomeDir, { recursive: true });
+  fs.mkdirSync(path.join(buildHomeDir, "AppData", "Roaming"), { recursive: true });
+  fs.mkdirSync(path.join(buildHomeDir, "AppData", "Local"), { recursive: true });
+
+  // Step 0: Sync version from app/cli/package.json to app/package.json
+  console.log("0️⃣  Syncing version to app/package.json...");
+  const cliPkg = JSON.parse(fs.readFileSync(path.join(cliDir, "package.json"), "utf8"));
+  const appPkgPath = path.join(appDir, "package.json");
+  const appPkg = JSON.parse(fs.readFileSync(appPkgPath, "utf8"));
+  if (appPkg.version !== cliPkg.version) {
+    appPkg.version = cliPkg.version;
+    fs.writeFileSync(appPkgPath, JSON.stringify(appPkg, null, 2) + "\n");
+    console.log(`✅ Version synced: ${cliPkg.version}\n`);
+  } else {
+    console.log(`✅ Version already synced: ${cliPkg.version}\n`);
+  }
+
+  // Step 1: Build app with Next.js (workspace tracing root → traced node_modules in standalone).
+  console.log("1️⃣  Building Next.js app...");
+  try {
+    execSync("npm run build", {
+      stdio: "inherit",
+      cwd: appDir,
+      env: {
+        ...process.env,
+        HOME: buildHomeDir,
+        USERPROFILE: buildHomeDir,
+        APPDATA: path.join(buildHomeDir, "AppData", "Roaming"),
+        LOCALAPPDATA: path.join(buildHomeDir, "AppData", "Local"),
+        NEXT_DIST_DIR: buildDistDirName,
+        NEXT_TRACING_ROOT_MODE: "workspace",
+      }
+    });
+    console.log("✅ Next.js build completed\n");
+  } catch (error) {
+    console.error("❌ Next.js build failed");
+    process.exit(1);
+  }
+
+  // Step 2: Clean old app/cli/app if exists
+  console.log("2️⃣  Cleaning old app/cli/app...");
+  if (fs.existsSync(cliAppDir)) {
+    fs.rmSync(cliAppDir, { recursive: true, force: true });
+  }
+  console.log("✅ Cleaned\n");
+
+  // Step 3: Copy Next.js standalone build to app/cli/app.
+  // Newer Next.js standalone output writes server.js/package.json plus .next/, src/, and
+  // node_modules/ directly under .next/standalone. Older builds may still use a nested app/.
+  console.log("3️⃣  Copying Next.js standalone build to app/cli/app...");
+  try {
+    copyStandaloneBuild(appDir, buildDistDir, cliAppDir);
+  } catch (error) {
+    console.error("❌ Next.js standalone build not found under .next/standalone");
+    console.error("Expected either .next/standalone/server.js or .next/standalone/app/");
+    process.exit(1);
+  }
+  console.log("✅ Copied standalone build\n");
+
+  // Step 3a: Copy custom server (injects real socket IP, strips spoofable XFF).
+  const customServerSrc = path.join(appDir, "custom-server.js");
+  if (fs.existsSync(customServerSrc)) {
+    fs.copyFileSync(customServerSrc, path.join(cliAppDir, "custom-server.js"));
+    console.log("✅ Copied custom-server.js\n");
+  } else {
+    console.warn("⚠️  custom-server.js not found — server will run without real-IP injection\n");
+  }
+
+  // Step 3b: Ensure sql.js (pure JS fallback) bundled in app/cli/app/node_modules.
+  // Strip better-sqlite3 (native) — it lives in ~/.9router/runtime to avoid
+  // Windows EBUSY during global CLI updates. node:sqlite (Node ≥22.5) is also
+  // available as a no-install middle tier.
+  console.log("3️⃣ b Configuring SQLite drivers...");
+  function ensureModuleInBundle(pkg) {
+    const dest = path.join(cliAppDir, "node_modules", pkg);
+    if (fs.existsSync(dest)) {
+      console.log(`✅ ${pkg} already bundled`);
+      return;
+    }
+    const candidates = [
+      path.join(appDir, "node_modules", pkg),
+      path.join(rootDir, "node_modules", pkg),
+    ];
+    const src = candidates.find((p) => fs.existsSync(p));
+    if (!src) {
+      console.warn(`⚠️  ${pkg} not found locally — bundle will rely on node:sqlite or runtime install`);
+      return;
+    }
+    fs.mkdirSync(path.dirname(dest), { recursive: true });
+    copyRecursive(src, dest);
+    console.log(`✅ Bundled ${pkg}`);
+  }
+  ensureModuleInBundle("sql.js");
+  // `open` is external (see serverExternalPackages in next.config.mjs), so it must exist in
+  // the bundle's node_modules or every importer throws MODULE_NOT_FOUND at runtime. Output
+  // tracing normally copies it; this is the same belt-and-braces guard used for sql.js.
+  ensureModuleInBundle("open");
+  const betterDir = path.join(cliAppDir, "node_modules", "better-sqlite3");
+  if (fs.existsSync(betterDir)) {
+    fs.rmSync(betterDir, { recursive: true, force: true });
+    console.log("✅ Stripped better-sqlite3 (lives in ~/.9router/runtime)");
+  }
+  console.log("");
+
+  // Step 4: Copy static files
+  console.log("4️⃣  Copying static files...");
+  const staticSrc = path.join(appDir, ".next", "static");
+  const staticSrcResolved = path.join(buildDistDir, "static");
+  const staticDest = path.join(cliAppDir, buildDistDirName, "static");
+  if (fs.existsSync(staticSrcResolved) || fs.existsSync(staticSrc)) {
+    copyRecursive(fs.existsSync(staticSrcResolved) ? staticSrcResolved : staticSrc, staticDest);
+    console.log("✅ Copied static files\n");
+  } else {
+    console.log("⏭️  No static files found\n");
+  }
+
+  // Step 5: Copy public folder if exists
+  console.log("5️⃣  Copying public folder...");
+  const publicSrc = path.join(appDir, "public");
+  const publicDest = path.join(cliAppDir, "public");
+  if (fs.existsSync(publicSrc)) {
+    copyRecursive(publicSrc, publicDest);
+    console.log("✅ Copied public folder\n");
+  } else {
+    console.log("⏭️  No public folder found\n");
+  }
+
+  // Step 6: Copy vendor-chunks (required for production)
+  console.log("6️⃣  Copying vendor-chunks...");
+  const vendorChunksSrc = path.join(appDir, ".next", "server", "vendor-chunks");
+  const vendorChunksSrcResolved = path.join(buildDistDir, "server", "vendor-chunks");
+  const vendorChunksDest = path.join(cliAppDir, buildDistDirName, "server", "vendor-chunks");
+  if (fs.existsSync(vendorChunksSrcResolved) || fs.existsSync(vendorChunksSrc)) {
+    copyRecursive(fs.existsSync(vendorChunksSrcResolved) ? vendorChunksSrcResolved : vendorChunksSrc, vendorChunksDest);
+    console.log("✅ Copied vendor-chunks\n");
+  } else {
+    console.log("⏭️  No vendor-chunks found\n");
+  }
+
+  // Step 6b: Merge the complete generated server tree. Next.js standalone output
+  // is trace-pruned and can omit route modules or chunks loaded dynamically.
+  console.log("6️⃣ b Copying complete server artifacts...");
+  mergeServerArtifacts(buildDistDir, cliAppDir);
+  assertRequiredApiArtifacts(cliAppDir);
+  console.log("✅ Copied complete server artifacts\n");
+
+  // Step 7: Copy MITM server files (not bundled by Next.js standalone)
+  console.log("7️⃣  Copying MITM server files...");
+  const mitmSrc = path.join(appDir, "src", "mitm");
+  const mitmDest = path.join(cliAppDir, "src", "mitm");
+  if (fs.existsSync(mitmSrc)) {
+    copyRecursive(mitmSrc, mitmDest);
+    console.log("✅ Copied MITM files\n");
+  } else {
+    console.log("⏭️  No MITM files found\n");
+  }
+
+  // Step 7b: Copy standalone updater (headless Node process for install progress)
+  console.log("7️⃣ b Copying updater files...");
+  const updaterSrc = path.join(appDir, "src", "lib", "updater");
+  const updaterDest = path.join(cliAppDir, "src", "lib", "updater");
+  if (fs.existsSync(updaterSrc)) {
+    copyRecursive(updaterSrc, updaterDest);
+    console.log("✅ Copied updater files\n");
+  } else {
+    console.log("⏭️  No updater files found\n");
+  }
+
+  // Step 8: Build MITM server (config driven - see app/cli/scripts/buildMitm.js)
+  console.log("8️⃣  Building MITM server...");
+  try {
+    execSync("node scripts/buildMitm.js", { stdio: "inherit", cwd: cliDir });
+    console.log("✅ MITM server build completed\n");
+  } catch (error) {
+    console.error("❌ MITM build failed");
+    process.exit(1);
+  }
+
+  console.log("✨ CLI package build completed!");
+  console.log(`📁 Output: ${cliAppDir}`);
+
+  try {
+    const { execSync: exec } = require("child_process");
+    const size = exec(`du -sh "${cliAppDir}"`, { encoding: "utf8" }).trim();
+    console.log(`📊 Package size: ${size.split("\t")[0]}`);
+  } catch (e) {
+    // Silent fail on size check
+  }
 }
 
-// Step 6: Copy vendor-chunks (required for production)
-console.log("6️⃣  Copying vendor-chunks...");
-const vendorChunksSrc = path.join(appDir, ".next", "server", "vendor-chunks");
-const vendorChunksSrcResolved = path.join(buildDistDir, "server", "vendor-chunks");
-const vendorChunksDest = path.join(cliAppDir, buildDistDirName, "server", "vendor-chunks");
-if (fs.existsSync(vendorChunksSrcResolved) || fs.existsSync(vendorChunksSrc)) {
-  copyRecursive(fs.existsSync(vendorChunksSrcResolved) ? vendorChunksSrcResolved : vendorChunksSrc, vendorChunksDest);
-  console.log("✅ Copied vendor-chunks\n");
-} else {
-  console.log("⏭️  No vendor-chunks found\n");
-}
+module.exports = {
+  assertRequiredApiArtifacts,
+  copyStandaloneBuild,
+  mergeServerArtifacts,
+};
 
-// Step 7: Copy MITM server files (not bundled by Next.js standalone)
-console.log("7️⃣  Copying MITM server files...");
-const mitmSrc = path.join(appDir, "src", "mitm");
-const mitmDest = path.join(cliAppDir, "src", "mitm");
-if (fs.existsSync(mitmSrc)) {
-  copyRecursive(mitmSrc, mitmDest);
-  console.log("✅ Copied MITM files\n");
-} else {
-  console.log("⏭️  No MITM files found\n");
-}
-
-// Step 7b: Copy standalone updater (headless Node process for install progress)
-console.log("7️⃣ b Copying updater files...");
-const updaterSrc = path.join(appDir, "src", "lib", "updater");
-const updaterDest = path.join(cliAppDir, "src", "lib", "updater");
-if (fs.existsSync(updaterSrc)) {
-  copyRecursive(updaterSrc, updaterDest);
-  console.log("✅ Copied updater files\n");
-} else {
-  console.log("⏭️  No updater files found\n");
-}
-
-// Step 8: Build MITM server (config driven - see app/cli/scripts/buildMitm.js)
-console.log("8️⃣  Building MITM server...");
-try {
-  execSync("node scripts/buildMitm.js", { stdio: "inherit", cwd: cliDir });
-  console.log("✅ MITM server build completed\n");
-} catch (error) {
-  console.error("❌ MITM build failed");
-  process.exit(1);
-}
-
-console.log("✨ CLI package build completed!");
-console.log(`📁 Output: ${cliAppDir}`);
-
-try {
-  const { execSync: exec } = require("child_process");
-  const size = exec(`du -sh "${cliAppDir}"`, { encoding: "utf8" }).trim();
-  console.log(`📊 Package size: ${size.split("\t")[0]}`);
-} catch (e) {
-  // Silent fail on size check
+if (require.main === module) {
+  buildCliPackage();
 }
diff --git a/tests/unit/cli-build-artifacts.test.js b/tests/unit/cli-build-artifacts.test.js
new file mode 100644
index 00000000..0644a1cd
--- /dev/null
+++ b/tests/unit/cli-build-artifacts.test.js
@@ -0,0 +1,141 @@
+import assert from "node:assert/strict";
+import { createRequire } from "node:module";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+
+let testApi;
+try {
+  testApi = await import("vitest");
+} catch (error) {
+  if (error.code !== "ERR_MODULE_NOT_FOUND") throw error;
+  testApi = await import("node:test");
+}
+const { afterEach, describe, it } = testApi;
+
+const require = createRequire(import.meta.url);
+const {
+  assertRequiredApiArtifacts,
+  copyStandaloneBuild,
+  mergeServerArtifacts,
+} = require("../../cli/scripts/build-cli.js");
+
+const tempDirs = [];
+
+function createTempDir() {
+  const tempDir = fs.mkdtempSync(path.join(os.tmpdir(), "9router-cli-build-"));
+  tempDirs.push(tempDir);
+  return tempDir;
+}
+
+function writeFixture(root, relativePath, contents = relativePath) {
+  const filePath = path.join(root, relativePath);
+  fs.mkdirSync(path.dirname(filePath), { recursive: true });
+  fs.writeFileSync(filePath, contents);
+  return filePath;
+}
+
+function createCompleteServer(buildDistDir) {
+  const serverDir = path.join(buildDistDir, "server");
+  writeFixture(serverDir, "app/api/v1/chat/completions/route.js", "chat route");
+  writeFixture(serverDir, "app/api/v1/messages/route.js", "messages route");
+  writeFixture(serverDir, "chunks/openai-provider.js", "openai chunk");
+  writeFixture(serverDir, "chunks/anthropic-provider.js", "anthropic chunk");
+  return serverDir;
+}
+
+afterEach(() => {
+  for (const tempDir of tempDirs.splice(0)) {
+    fs.rmSync(tempDir, { recursive: true, force: true });
+  }
+});
+
+describe("CLI build server artifacts", () => {
+  for (const { name, standalonePath } of [
+    {
+      name: "legacy nested app",
+      standalonePath: (appDir, buildDistDir) => path.join(appDir, ".next", "standalone", "app"),
+    },
+    {
+      name: "Next 16 workspace",
+      standalonePath: (appDir, buildDistDir) => path.join(buildDistDir, "standalone", path.basename(appDir)),
+    },
+  ]) {
+    it(`merges complete API routes and provider chunks for the ${name} layout`, () => {
+      const root = createTempDir();
+      const appDir = path.join(root, "9router");
+      const buildDistDir = path.join(appDir, ".next-cli-build");
+      const cliAppDir = path.join(root, "cli-app");
+      const standaloneDir = standalonePath(appDir, buildDistDir);
+
+      writeFixture(standaloneDir, "server.js", "standalone server");
+      writeFixture(
+        standaloneDir,
+        ".next-cli-build/server/app/api/v1/chat/completions/route.js",
+        "standalone chat route",
+      );
+      createCompleteServer(buildDistDir);
+
+      copyStandaloneBuild(appDir, buildDistDir, cliAppDir);
+      mergeServerArtifacts(buildDistDir, cliAppDir);
+      assertRequiredApiArtifacts(cliAppDir);
+
+      const packagedServer = path.join(cliAppDir, ".next-cli-build", "server");
+      assert.equal(
+        fs.readFileSync(path.join(packagedServer, "app/api/v1/messages/route.js"), "utf8"),
+        "messages route",
+      );
+      assert.equal(
+        fs.readFileSync(path.join(packagedServer, "chunks/openai-provider.js"), "utf8"),
+        "openai chunk",
+      );
+      assert.equal(
+        fs.readFileSync(path.join(packagedServer, "chunks/anthropic-provider.js"), "utf8"),
+        "anthropic chunk",
+      );
+    });
+  }
+
+  it("merges idempotently without removing standalone-generated files", () => {
+    const root = createTempDir();
+    const buildDistDir = path.join(root, ".next-cli-build");
+    const cliAppDir = path.join(root, "cli-app");
+    const packagedServer = path.join(cliAppDir, ".next-cli-build", "server");
+
+    createCompleteServer(buildDistDir);
+    writeFixture(packagedServer, "standalone-only.js", "keep me");
+
+    mergeServerArtifacts(buildDistDir, cliAppDir);
+    mergeServerArtifacts(buildDistDir, cliAppDir);
+
+    assert.equal(
+      fs.readFileSync(path.join(packagedServer, "standalone-only.js"), "utf8"),
+      "keep me",
+    );
+    assert.equal(
+      fs.readFileSync(path.join(packagedServer, "app/api/v1/messages/route.js"), "utf8"),
+      "messages route",
+    );
+  });
+
+  it("reports the missing required API route artifact path", () => {
+    const root = createTempDir();
+    const buildDistDir = path.join(root, ".next-cli-build");
+    const cliAppDir = path.join(root, "cli-app");
+
+    writeFixture(
+      path.join(buildDistDir, "server"),
+      "app/api/v1/chat/completions/route.js",
+      "chat route",
+    );
+    mergeServerArtifacts(buildDistDir, cliAppDir);
+
+    assert.throws(
+      () => assertRequiredApiArtifacts(cliAppDir),
+      (error) => error.message.includes(path.join(
+        cliAppDir,
+        ".next-cli-build/server/app/api/v1/messages/route.js",
+      )),
+    );
+  });
+});