# Prompt to Add a Sitemap and robots.txt

> AI agent prompt to add a dynamically generated sitemap.xml and a correct robots.txt to a Next.js or Astro project for better search indexing.

**Type:** Prompt  
**Tools:** Cursor, Claude Code, Codex, Windsurf  
**Stack:** Next.js, Astro, TypeScript  
**Difficulty:** easy  
**Updated:** 2026-06-08

---

Give this prompt to your agent to add a standards-compliant `sitemap.xml` and
`robots.txt` — handling dynamic routes, priority values, and lastmod dates
without using a paid third-party service.

## Main Prompt

```txt title="Main Prompt"
You are working in a Next.js 15 App Router project with TypeScript.
The site has static pages (/, /about, /pricing) and dynamic blog posts in `src/content/blog/`.

Task: add sitemap.xml and robots.txt using only Next.js built-in file conventions.

Requirements:
- Create `src/app/sitemap.ts` (NOT `.xml`) using the Next.js `MetadataRoute.Sitemap` return type.
  - Static URLs: `/`, `/about`, `/pricing` with `priority: 1.0` and `changeFrequency: 'monthly'`.
  - Dynamic URLs: read all MDX files from `src/content/blog/` using `getCollection('blog')` from
    `astro:content` — wait, this is Next.js, so use `fs` + `gray-matter` to read frontmatter.
  - For each post, return `{ url, lastModified, changeFrequency: 'weekly', priority: 0.8 }`.
  - `url` must be an absolute URL using the `NEXT_PUBLIC_SITE_URL` environment variable.
- Create `src/app/robots.ts` (NOT `.txt`) using the `MetadataRoute.Robots` return type.
  - Allow all crawlers for `/*`.
  - Disallow `/api/*` and `/admin/*` for all crawlers.
  - Set `sitemap` to the absolute sitemap URL.
- Add `NEXT_PUBLIC_SITE_URL=https://example.com` to `.env.example`.
- Do NOT install `next-sitemap` or any sitemap package.

Stop and list all files before writing code.
```

## Implementation Notes

- `sitemap.ts` and `robots.ts` in the `app/` directory are Next.js 13.3+ file conventions; they
  must export a default function that returns the typed metadata object — not a Response or string.
- If `NEXT_PUBLIC_SITE_URL` is undefined at build time, the sitemap will contain relative URLs
  which are invalid per the Sitemap protocol — validate with a startup check.
- `lastModified` should be a `Date` object, not a string; Next.js serializes it to ISO 8601.

## Expected File Changes

```txt
src/app/sitemap.ts              (new)
src/app/robots.ts               (new)
src/lib/blog.ts                 (new or edited — getAllPosts helper)
.env.example                    (edited)
```

## Acceptance Criteria

- `GET /sitemap.xml` returns valid XML with all static and dynamic URLs as absolute URLs.
- `GET /robots.txt` includes `Disallow: /api/` and `Sitemap: https://example.com/sitemap.xml`.
- Adding a new blog post MDX file causes its URL to appear in the sitemap after `bun run build`.
- The sitemap validates at https://www.xml-sitemaps.com/validate-xml-sitemap.html.

## Test Commands

```bash
bun run build && bun run start
curl http://localhost:3000/sitemap.xml | xmllint --format - | head -40
curl http://localhost:3000/robots.txt
# confirm /api/ is disallowed and sitemap URL is absolute
bun run typecheck
```

## Common AI Mistakes

- Creating a static `public/sitemap.xml` file instead of the dynamic `src/app/sitemap.ts` convention.
- Using relative URLs in the sitemap (e.g., `/blog/my-post`) — sitemaps require absolute URLs.
- Installing `next-sitemap` when the prompt explicitly disallows it.
- Setting `robots.txt` to disallow all crawlers (`Disallow: /`), which de-indexes the entire site.

## Fix Prompt

```txt title="Fix Prompt"
The sitemap contains relative URLs or robots.txt disallows too much. Fix in order:
1. In `src/app/sitemap.ts`, construct every URL as:
   `const base = process.env.NEXT_PUBLIC_SITE_URL ?? 'https://example.com'; url: \`\${base}/blog/\${post.slug}\``
2. In `src/app/robots.ts`, verify the rules object:
   `{ userAgent: '*', allow: '/', disallow: ['/api/', '/admin/'] }`.
3. Confirm `sitemap.ts` exports a default async function (not a named export).
Show only the corrected diff.
```