Tag and Multi-tag

The coloured picklist Property kind. One "Tags" property, with settings for single vs. multiple picks and a Collection-only vs. shared Global Tags pool.

Tags is a coloured option you pick from a list — the same idea as a select in other tools. They're perfect for things like mood, priority, project, or symptoms: a fixed-ish set of choices you want to filter and read at a glance.

Add one from + Add a property → Tags. Every Tags property starts out letting you pick one option, scoped to this Collection only — two settings on the property (open its settings from the Collection builder or an Entry) change that, and you can flip either one at any time without losing your existing values.

One or many?

Open the property's settings and flip Allow multiple tags:

Off — pick one option (Mood: happy).
On — pick several (Symptoms: headache, tired).

Flipping it keeps your data: switching on keeps the chosen option (now the first item in the list); switching off keeps just the first option that was picked.

Just this Collection, or shared everywhere?

Open the property's settings and flip Use global tag pool:

Off (scoped) — the options live on this property, on this Collection. A Dish Collection's "Diet" tag has vegetarian / pescetarian / carnivore, and those options exist only there. Another Collection's tags are completely separate.
On (global) — the options come from your one shared pool, managed on the Global tags tab of Collections. Use this for labels you want to reuse across many different Collections — a #project or #area that means the same thing whether you're logging a workout, a note, or a meal.

Rule of thumb: if the options only make sense for one tracker, leave Use global tag pool off. If you'd retype the same labels on several trackers, turn it on.

Switching either way keeps your data, but they work a little differently under the hood:

Turning it on copies this property's own options straight into the shared pool — they're now managed from the Global tags tab (and visible to any other Tags property that also uses the pool), and your entries keep pointing at the exact same options.
Turning it off copies every global option this property's entries actually use into a fresh, Collection-only list — nothing is deleted from your global pool, this property just gets its own independent copy to manage from here on.

Using a tag

Wherever you log or edit an Entry — the entry page, a feed card, or the database table — a tag field shows your current pick as a coloured pill. Click it to open the picker:

Search the list, or just start typing.
Click an option to choose it (with Allow multiple tags on, the menu stays open so you can add more; off, picking one closes it).
Create one — type a name that doesn't exist yet and hit Create. With Use global tag pool off the new option is added to this property; on, it joins your shared pool.
Recolour, rename, or delete any option from the ⋯ menu next to it.

With Allow multiple tags on, each chosen pill has an × to remove it.

Where options come from

You don't set options up in advance — you create them as you tag, right from the picker on an entry (just like Notion). Type a name that doesn't exist yet and hit Create: with Use global tag pool off the option is added to that property; on, it joins your shared pool. Manage the shared pool any time on the Global tags tab.

The Global tags tab

Open Collections in the sidebar and pick the Global tags tab to manage your shared pool in one place — add new tags, recolour and rename them, drag to reorder, or delete. Every Tags property with Use global tag pool on, across all your Collections, picks from this same list, so a colour or rename here shows up everywhere at once.

Deleting an option

Deleting a tag option removes it from the picker. Entries that had it simply stop showing it — nothing else on the entry changes.

Asking your AI to tag things

Your AI sees the options you already have and picks from them — ask it to tag a task "as due tomorrow" and it will reach for your existing tomorrow option rather than inventing a near-duplicate beside it. It matches on what you mean, not on exact spelling.

If nothing in the list fits, it creates a new option and tells you it did.

It can also tidy the list itself: "rename that tag to X" changes the option everywhere it's used, and "delete the tag you just created" removes it from the pool for good. Those are different from clearing a tag off one entry — say which you want and it'll do exactly that.