# Page Not Found

The URL `start/install/agent` does not exist.

You might be looking for one of these pages:
- [Add an environment to an existing installation](https://docs.portainer.io/start/agent.md)
- [Upgrading Agent-only deployments](https://docs.portainer.io/start/upgrade/tobe/agent.md)
- [Install Portainer BE](https://docs.portainer.io/start/install.md)
- [Install Portainer CE](https://docs.portainer.io/start/install-ce.md)
- [Set up a new Portainer BE Server installation](https://docs.portainer.io/start/install/server.md)

## How to find the correct page

1. **Browse the full index**: [/sitemap.md](https://docs.portainer.io/sitemap.md) - Complete documentation index
2. **View the full content**: [/llms-full.txt](https://docs.portainer.io/llms-full.txt) - Full content export

## Tips for requesting documentation

- For markdown responses, append `.md` to URLs (e.g., `/start/agent.md`)
- Use `Accept: text/markdown` header for content negotiation