Can a tag tell others you are in a meeting?
Yes, by setting a status in whatever tool your colleagues already watch, rather than by changing anything on your own phone. Silencing a phone protects you; a status protects the interruption. Those are two separate automations, and people who build only the first keep getting interrupted anyway.
Two different problems
Silencing your phone stops the phone interrupting you. It does nothing about the colleague who walks over, or the message that arrives and sits unanswered looking rude.
A status tells other people something. It is a message outwards, and no amount of focus mode on your own device produces one.
Most people build the first, keep getting interrupted, and conclude that automation does not help. The missing half is the second.
The signal has to reach them
A status is only useful in the place your colleagues already look. That is usually the messaging tool the team lives in, occasionally a shared calendar, and almost never anywhere you would have to ask them to check.
So the automation is: tap, set status in that tool. Whether that is possible depends entirely on what the tool exposes to automation, and it is worth confirming before writing a tag.
If nothing exposes a status, the honest fallback is physical: a card on the door or the monitor, which needs no integration and is read by everybody.
Turning it off is the hard part
A status you forget to clear is worse than no status, because it teaches people to ignore it.
Prefer a status with a duration, so that it expires by itself. If the tool allows only an open ended status, pair the automation with a timer that reminds you.
A second tag by the door, tapped on the way out, sounds symmetrical and rarely survives. The tap you remember is the one on the way in.
The tag on the door
In a shared office, the useful placement is not your desk but the door or the room, where a visitor sees it before knocking.
A tag there can open a booking page, show who has the room, or carry the number to call rather than knock. That is a status for people who are not on your team and never will be in your messaging tool.
Print matters more than the tag here. Whoever is about to knock reads the card, and the tap is for the one in ten who wants the detail.
Frequently asked questions
Why does silencing my phone not stop interruptions?
Because it is a message to your phone, not to your colleagues. Interruptions from people need a signal people can see.
What if our tools have no status to set?
Then a printed card on the door does the job with no integration at all, and everybody can read it.
Should a second tag clear the status?
It rarely gets tapped. A status with a duration that expires by itself is far more reliable.
Is this worth it for one person?
Only in a shared space. Alone at home, silencing the phone is the whole of the problem.