mailbox-helper

Helps people who don't speak the local language (mainly migrants) understand their letters: it explains each one in their language, colors it by urgency and files it privately on their NAS.

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Inspiration

When people move to a new country, the hardest letters are the official ones. A letter from the tax office, the energy company or the city can carry a deadline, a fine or an important notice, and if a person doesn’t understand it, they can’t act on it. Many migrants don’t know the language at all, or know a little but can’t be sure they understood a letter correctly. Many people use online translators on their phone or the web, but then their personal information could be leaked. They also can’t access the letters instantly later, because nothing is stored. Even when the letters are saved on a computer or somewhere else, there is no link between related letters or letters from the same sender. In the end, it still leaves a pile of paper with no order.

What it does

mailbox-helper turns the UGREEN AI NAS into a private letter assistant:

  • Reads a photographed or PDF letter in any language (OCR or PDF).
  • Explains it in the user's own language in up to 5 calm sentences, and shows the deadlines and amounts exactly as written.
  • Rates urgency from the letter alone: 🔴 Urgent, 🟠 Has a deadline, 🔵 For your records, ⚪ Advert, ❔ Couldn't tell.
  • Links earlier letters from the same sender, so a second payment reminder is connected to the original bill.
  • Files the original in the right folder (Bills, Contracts, Government, Insurance…) with a colour tag and a short note, only after one approval.
  • "What's due": on request, it reads the saved notes back as a short overview of upcoming deadlines. Each family member has a private Mailbox in their own NAS account. The skill gives no advice and drafts no replies. For serious letters, it says what the letter asks for and by when, and calmly suggests a counselling service or a lawyer.

How we built it

  1. Idea: I came up with the idea from my own life: I moved to Germany and struggle to understand official letters.
  2. Checking it was possible: before building anything, I checked every feature against UGREEN's official capability catalog (the list of actions the AI NAS can really do), so the skill uses only real NAS features: 21 of its 78 actions.
  3. Building: I designed the flow and made the decisions, and I used Grok Bot (an AI assistant) to write the skill files with me: one SKILL.md that hands each step to the NAS's own AI experts (photo-agent, document-agent, file-agent, knowledge-agent), plus reference files with the rules, wording and edge cases. Everything is written in Markdown using UGREEN's Uliya skill kit.
  4. Checking: I ran the kit's official checker (a Node.js script) until it showed no errors and no warnings, then tested the logic with six step-by-step walkthroughs using made-up letters.
  5. Improving: I reviewed every feature and removed what the NAS or the skill couldn't do reliably, such as drafting replies.
  6. Writing: ChatGPT gave wording ideas for the skill description, and Claude helped with the wording of my proposal PDF.

Challenges we ran into

  • Staying 100% inside the NAS's real capabilities. Every feature had to match UGREEN's official action catalog. For example, the extract action accepts files, not text, so for photographed letters the skill reads the OCR text itself instead.
  • Never guessing. For someone who can't read the language, one wrong date or amount is worse than no answer. So if a needed result is missing, the steps that depend on it stop, and a blurry scan stops the process and asks for a better photo.
  • Helping without giving advice. Serious letters need serious replies, which a tool can't reliably give. We removed reply drafting and kept the skill to facts, urgency and filing.
  • Privacy in a family. Letters are personal, so each family member has a private Mailbox in their own NAS account.

Accomplishments that we're proud of

  • The skill passes UGREEN's official checker with no errors and no warnings.
  • Every feature uses a real NAS action, and nothing leaves the NAS.
  • It works with letters in any language and explains them in the user's own language.
  • A second payment reminder is automatically linked to the original bill and marked urgent, so the user sees the full story at once.

What we learned

  • Simple, calm and correct beats clever. Users who can't read the language need certainty more than extra features.
  • Checking what the platform can really do before building saves a lot of rework.
  • Saying "I couldn't read this, please take a better photo" is a feature, not a failure.

What's next for mailbox-helper

  • Testing on a real UGREEN AI NAS with real-looking letters.
  • A language setting for each family member.
  • Saving the translation next to the original letter and note.
  • Advanced user rules, such as custom folders.

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