diff --git a/packages/@apphosting/adapter-angular/package.json b/packages/@apphosting/adapter-angular/package.json
index 65ed96ba..2cdd1212 100644
--- a/packages/@apphosting/adapter-angular/package.json
+++ b/packages/@apphosting/adapter-angular/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@apphosting/adapter-angular",
-  "version": "17.2.15",
+  "version": "17.2.16",
   "main": "dist/index.js",
   "description": "Experimental addon to the Firebase CLI to add web framework support",
   "repository": {
diff --git a/packages/@apphosting/adapter-angular/src/utils.ts b/packages/@apphosting/adapter-angular/src/utils.ts
index 52ecc563..e5be7de1 100644
--- a/packages/@apphosting/adapter-angular/src/utils.ts
+++ b/packages/@apphosting/adapter-angular/src/utils.ts
@@ -175,7 +175,10 @@ function extractManifestOutput(output: string): string {
   if (start === -1 || end === -1 || start > end) {
     throw new Error(`Failed to find valid JSON object from build output: ${output}`);
   }
-  return stripAnsi(output.substring(start, end + 1));
+  // Clean the raw json string by removing the "web:build:" prefixes for a Turbo build
+  const prefixRegex = /\n?web:build:/g;
+  const cleanedOutput = output.substring(start, end + 1).replace(prefixRegex, "");
+  return stripAnsi(cleanedOutput);
 }
 
 /**
diff --git a/packages/@apphosting/adapter-nextjs/package.json b/packages/@apphosting/adapter-nextjs/package.json
index 54a6ad53..3490ab47 100644
--- a/packages/@apphosting/adapter-nextjs/package.json
+++ b/packages/@apphosting/adapter-nextjs/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@apphosting/adapter-nextjs",
-  "version": "14.0.17",
+  "version": "14.0.18",
   "main": "dist/index.js",
   "description": "Experimental addon to the Firebase CLI to add web framework support",
   "repository": {
diff --git a/packages/@apphosting/adapter-nextjs/src/bin/build.spec.ts b/packages/@apphosting/adapter-nextjs/src/bin/build.spec.ts
index 8fb1177f..e98d9f52 100644
--- a/packages/@apphosting/adapter-nextjs/src/bin/build.spec.ts
+++ b/packages/@apphosting/adapter-nextjs/src/bin/build.spec.ts
@@ -164,6 +164,95 @@ outputFiles:
       async () => await validateOutputDirectory(outputBundleOptions, path.join(tmpDir, ".next")),
     );
   });
+  it(".apphosting gitignored correctly in a monorepo setup", async () => {
+    const { generateBuildOutput } = await importUtils;
+    const files = {
+      ".next/standalone/apps/next-app/standalonefile": "",
+      ".next/static/staticfile": "",
+    };
+    generateTestFiles(tmpDir, files);
+    const standaloneAppPath = path.join(tmpDir, ".next", "standalone", "apps", "next-app");
+    await generateBuildOutput(
+      tmpDir,
+      "apps/next-app",
+      {
+        bundleYamlPath: path.join(tmpDir, ".apphosting", "bundle.yaml"),
+        outputDirectoryBasePath: path.join(tmpDir, ".apphosting"),
+        outputDirectoryAppPath: standaloneAppPath,
+        outputPublicDirectoryPath: path.join(standaloneAppPath, "public"),
+        outputStaticDirectoryPath: path.join(standaloneAppPath, ".next", "static"),
+        serverFilePath: path.join(standaloneAppPath, "server.js"),
+      },
+      path.join(tmpDir, ".next"),
+      defaultNextVersion,
+      adapterMetadata,
+    );
+
+    const expectedFiles = {
+      ".gitignore": "/.apphosting/",
+    };
+    const expectedPartialYaml = {
+      version: "v1",
+      runConfig: { runCommand: "node .next/standalone/apps/next-app/server.js" },
+    };
+    validateTestFiles(tmpDir, expectedFiles);
+    validatePartialYamlContents(tmpDir, ".apphosting/bundle.yaml", expectedPartialYaml);
+  });
+
+  it(".apphosting gitignored without existing .gitignore file", async () => {
+    const { generateBuildOutput, validateOutputDirectory } = await importUtils;
+    const files = {
+      // .next/standalone/.next/ must be created beforehand otherwise
+      // generateBuildOutput will attempt to copy
+      // .next/ into .next/standalone/.next
+      ".next/standalone/.next/package.json": "",
+      ".next/static/staticfile": "",
+    };
+    generateTestFiles(tmpDir, files);
+    await generateBuildOutput(
+      tmpDir,
+      tmpDir,
+      outputBundleOptions,
+      path.join(tmpDir, ".next"),
+      defaultNextVersion,
+      adapterMetadata,
+    );
+    await validateOutputDirectory(outputBundleOptions, path.join(tmpDir, ".next"));
+
+    const expectedFiles = {
+      ".gitignore": "/.apphosting/",
+    };
+    validateTestFiles(tmpDir, expectedFiles);
+  });
+  it(".apphosting gitignored in existing .gitignore file", async () => {
+    const { generateBuildOutput, validateOutputDirectory } = await importUtils;
+    const files = {
+      // .next/standalone/.next/ must be created beforehand otherwise
+      // generateBuildOutput will attempt to copy
+      // .next/ into .next/standalone/.next
+      ".next/standalone/.next/package.json": "",
+      ".next/static/staticfile": "",
+      ".gitignore": "/.next/",
+    };
+    generateTestFiles(tmpDir, files);
+    await generateBuildOutput(
+      tmpDir,
+      tmpDir,
+      outputBundleOptions,
+      path.join(tmpDir, ".next"),
+      defaultNextVersion,
+      {
+        adapterPackageName: "@apphosting/adapter-nextjs",
+        adapterVersion: "14.0.1",
+      },
+    );
+    await validateOutputDirectory(outputBundleOptions, path.join(tmpDir, ".next"));
+
+    const expectedFiles = {
+      ".gitignore": "/.next/\n/.apphosting/",
+    };
+    validateTestFiles(tmpDir, expectedFiles);
+  });
   it("expects directories and other files to be copied over", async () => {
     const { generateBuildOutput, validateOutputDirectory } = await importUtils;
     const files = {
@@ -188,10 +277,7 @@ outputFiles:
       outputBundleOptions,
       path.join(tmpDir, ".next"),
       defaultNextVersion,
-      {
-        adapterPackageName: "@apphosting/adapter-nextjs",
-        adapterVersion: "14.0.1",
-      },
+      adapterMetadata,
     );
     await validateOutputDirectory(outputBundleOptions, path.join(tmpDir, ".next"));
 
diff --git a/packages/@apphosting/adapter-nextjs/src/utils.ts b/packages/@apphosting/adapter-nextjs/src/utils.ts
index ed6cbc0a..3c6ab548 100644
--- a/packages/@apphosting/adapter-nextjs/src/utils.ts
+++ b/packages/@apphosting/adapter-nextjs/src/utils.ts
@@ -12,10 +12,10 @@ import {
   MiddlewareManifest,
 } from "./interfaces.js";
 import { NextConfigComplete } from "next/dist/server/config-shared.js";
-import { OutputBundleConfig } from "@apphosting/common";
+import { OutputBundleConfig, updateOrCreateGitignore } from "@apphosting/common";
 
 // fs-extra is CJS, readJson can't be imported using shorthand
-export const { copy, exists, writeFile, readJson, readdir, readFileSync, existsSync, mkdir } =
+export const { copy, exists, writeFile, readJson, readdir, readFileSync, existsSync, ensureDir } =
   fsExtra;
 
 // Loads the user's next.config.js file.
@@ -135,6 +135,10 @@ export async function generateBuildOutput(
     copyResources(appDir, opts.outputDirectoryAppPath, opts.bundleYamlPath),
     generateBundleYaml(opts, rootDir, nextVersion, adapterMetadata),
   ]);
+  // generateBundleYaml creates the output directory (if it does not already exist).
+  // We need to make sure it is gitignored.
+  const normalizedBundleDir = normalize(relative(rootDir, opts.outputDirectoryBasePath));
+  updateOrCreateGitignore(rootDir, [`/${normalizedBundleDir}/`]);
   return;
 }
 
@@ -181,7 +185,7 @@ async function generateBundleYaml(
   nextVersion: string,
   adapterMetadata: AdapterMetadata,
 ): Promise<void> {
-  await mkdir(opts.outputDirectoryBasePath);
+  await ensureDir(opts.outputDirectoryBasePath);
   const outputBundle: OutputBundleConfig = {
     version: "v1",
     runConfig: {
diff --git a/packages/@apphosting/common/package.json b/packages/@apphosting/common/package.json
index ed144d7b..28bfbf6e 100644
--- a/packages/@apphosting/common/package.json
+++ b/packages/@apphosting/common/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@apphosting/common",
-  "version": "0.0.6",
+  "version": "0.0.7",
   "description": "Shared library code for App Hosting framework adapters",
   "author": {
     "name": "Firebase",
diff --git a/packages/@apphosting/common/src/index.spec.ts b/packages/@apphosting/common/src/index.spec.ts
index 27bdbd57..3993469f 100644
--- a/packages/@apphosting/common/src/index.spec.ts
+++ b/packages/@apphosting/common/src/index.spec.ts
@@ -2,7 +2,56 @@ import assert from "assert";
 import fs from "fs";
 import path from "path";
 import os from "os";
-import { updateOrCreateGitignore } from "./index";
+import { getBuildOptions, updateOrCreateGitignore } from "./index";
+
+const originalCwd = process.cwd.bind(process);
+
+describe("get a set of build options", () => {
+  const mockCwd = "/fake/project/";
+  beforeEach(() => {
+    process.cwd = () => mockCwd;
+  });
+
+  afterEach(() => {
+    process.cwd = originalCwd;
+    delete process.env.MONOREPO_COMMAND;
+    delete process.env.MONOREPO_BUILD_ARGS;
+    delete process.env.GOOGLE_BUILDABLE;
+    delete process.env.MONOREPO_PROJECT;
+  });
+
+  it("returns monorepo build options when MONOREPO_COMMAND is set", () => {
+    process.env.MONOREPO_COMMAND = "turbo";
+    process.env.MONOREPO_BUILD_ARGS = "--filter=web,--env-mode=strict";
+    process.env.GOOGLE_BUILDABLE = "/workspace/apps/web";
+    process.env.MONOREPO_PROJECT = "web";
+
+    const expectedOptions = {
+      buildCommand: "turbo",
+      buildArgs: ["run", "build", "--filter=web", "--env-mode=strict"],
+      projectDirectory: "/workspace/apps/web",
+      projectName: "web",
+    };
+    assert.deepStrictEqual(
+      getBuildOptions(),
+      expectedOptions,
+      "Monorepo build options are incorrect",
+    );
+  });
+
+  it("returns standard build options when MONOREPO_COMMAND is not set", () => {
+    const expectedOptions = {
+      buildCommand: "npm",
+      buildArgs: ["run", "build"],
+      projectDirectory: process.cwd(),
+    };
+    assert.deepStrictEqual(
+      getBuildOptions(),
+      expectedOptions,
+      "Standard build options are incorrect",
+    );
+  });
+});
 
 describe("update or create .gitignore", () => {
   let tmpDir: string;
diff --git a/packages/@apphosting/common/src/index.ts b/packages/@apphosting/common/src/index.ts
index f16d32db..7ad051de 100644
--- a/packages/@apphosting/common/src/index.ts
+++ b/packages/@apphosting/common/src/index.ts
@@ -130,7 +130,7 @@ export function getBuildOptions(): BuildOptions {
   if (process.env.MONOREPO_COMMAND) {
     return {
       buildCommand: process.env.MONOREPO_COMMAND,
-      buildArgs: ["run", "build"].concat(process.env.MONOREPO_BUILD_ARGS?.split(".") || []),
+      buildArgs: ["run", "build"].concat(process.env.MONOREPO_BUILD_ARGS?.split(",") || []),
       projectDirectory: process.env.GOOGLE_BUILDABLE || "",
       projectName: process.env.MONOREPO_PROJECT,
     };