A tún is the yard between the houses. Everyone going anywhere on the farm walks across it. We want to build a yard like that for information that gets shared, where whatever works stays behind for the next person who needs it.
The idea in one picture
Drag the picture sideways to see all of it.
The core is open and shared. One file comes out of it, not a system to run. The file goes where the work already lives, and the folder is the access control. Pick a role above to see your part of the picture.
Tún is a framework without a framework: plain HTML, CSS and JavaScript, with no library to install or keep up to date. JavaScript is allowed but used only where it is needed. This picture did not need it: motion, choices and playback are pure CSS.
The reader
The reader opens the file with no licence, with nothing to install and with no network. The reply comes in an ordinary message, and that is enough: the next version gets better from it.
The community
A skill is a recipe that goes from house to house across the tún. Whoever uses it can make it a little better. What worked stays behind for the next person.
The host
Pick a host. Each line says what was measured there, and when.
The link to the file itself downloads it. In the preview the file runs, but nothing can be downloaded or printed from it. Measured 2026-10-08.
From a synced folder the file opens from disk and works fully. A OneDrive link in an email worked on PC, but on mobile nothing responded. Measured September 2026, on one phone.
A link pasted into a message and opened from the preview card worked on PC and mobile. The plain-text link under the card showed the source code. Measured September 2026.
A file in Atlassian Artifacts runs in a sandbox, on its own and inside a Confluence page. Data in a separate file does not load there. Anyone in the organisation with the link can open a new file. Measured 2026-10-13.
An attachment in the email app's preview on iPhone did not run code, but the static page stood and could be read. Build the file so it works without code. Measured 2026-09-28.
Downloaded and opened from disk, with no network, the file worked on PC and mobile. That is the base case. Everything else is a bonus.
A static site serves the file as it is, like this page. Measure what is actually delivered: an edge network can add a script to the page without you seeing it.
Detours
The detours are everything around a small sharing job. The PPTX by email, the Excel sheet, the Word report and the Power BI licence become one file that works on a phone too.
What the toolkit can do, and what is coming
- Available now Skills for the AI tool you already use. Plain Markdown in the open Agent Skills format. Claude Code and Gemini CLI load all of them. Iterate fast: build with AI, and anchor what works in the tún.
- Available now One file. Everything is inside, the numbers too. It works from a folder, an email or a USB stick.
- Available now Data in a file next to it. Swap the numbers without rebuilding the page.
- Available now Millions of rows in a small file. Ready-made totals for every filter, exact down to the øre.
- Available now A reply button in the file. A link that makes it easy to say what was wrong.
- Available now A note you edit in the browser and save as a new file, as an example. In SharePoint's preview it can only be read, on purpose.
- Planned Folder picker, backends and paid services. None of it is delivered yet.
Four steps
- 1 · You write
A skill is a recipe. It goes from house to house across the tún, and every cook can make it a little better. You write plain text in Markdown.
- 2 · Tún builds
Everything ends up inside one HTML file, the numbers too. The reader needs nothing installed, and no server has to be run.
- 3 · You put it somewhere
The folder is the lock on the door. Whoever has the key gets in, and the file follows the folder's permissions.
- 4 · Someone reads and replies
One reply in a message is enough. The next version gets better from it, and recipes that worked get passed on.
“How do I share an HTML file with one colleague?”
The file does not need a website of its own with its own sign-in. The access already exists in the folder or the link. What surprised us most was that the sharing route decides the outcome. The same file on the same phone gave three different answers.
Measured by hand in September 2026, with one phone, one Teams version and one chat client. Take the rows as data points. What another phone does, we do not know yet.
| Sharing route | PC | Mobile | What it means |
|---|---|---|---|
| Link pasted in a Teams message, opened from the preview card | ✓ works | ✓ works | The only link that worked on mobile. Use this one. |
| OneDrive link pasted in an email | ✓ works | ✗ inert | The page appeared, but nothing responded on mobile. |
| The plain-text link Teams draws under the card | ✗ no | ✗ no | Showed the source code. Same file, same message, wrong link. |
| Attachment in a chat, opened in the attachment viewer | ✓ works | ✗ source code | The attachment viewer is not a browser. |
| Same attachment, “Open in browser” on the phone | ✓ works | ✓ works | The file was portable all along. One tap fixed it. |
| File downloaded and opened from disk, with no network | ✓ works | ✓ works | The base case. Everything else is a bonus. |
Think of the preview as a shop window. In some windows you see the goods but cannot touch them. In others you only see the price tag, meaning the source code. Open the file in a browser and you are standing inside the shop.
How to share
Paste a link into a Teams message and open it from the card. If you get an attachment on the phone, tap “Open in browser”.
Build the file so it works without anything running. Then the worst that can happen is that it looks a little duller. This page is built that way. The only script is a small language switch.
What is measured, and what is direction
The sharing table is measured, on a small scale. The core and the file format are decided. The skills load in Claude Code and Gemini CLI. Backends, folder picker and paid services are direction, and none of it is delivered yet.
The core is free software under AGPL v3 or later, and the code is on GitHub. The documents you make are yours, along with the numbers in them, by the Artefact Exception. Each keeps a short source line that names Tún, and it does not have to be visible. A document must not itself be a rival generator.
Want to follow along? The contact link is on the front page.