Maestro’s Chair from LOGB, what does it do?

[Kataaaka]

The item in question is from LOGB:

Quote:

Maestro's Chair

Item 7
Enchantment Magical
Source Grand Bazaar pg. 70
Price 350 gp
Bulk 6
A maestro's chair is a traveler's chair with the impulse control upgrade and a small pipe organ installed into the frame. You can use the maestro's chair to make Performance checks in the same manner that you could use any mundane instrument, using both of your hands. When you make a Performance check using your chair, you gain a +1 item bonus to the check.

Activate Single Action Interact; Frequency once per 10 minutes; Effect You use your chair to Stride up to your chair's speed. If you have a composition cantrip that is currently active, you Sustain it as a free action.

So it can sustain a bard composition cantrip, but most composition cantrips are not meant to be sustained. The only exception seems to be Song of Marching, which doesn't do anything in encounter mode:

Song of Marching:

Song of Marching
Cantrip 3
Uncommon Bard Cantrip Composition Enchantment Mental
Source Advanced Player's Guide pg. 228
Cast Single Action verbal
Area 60-foot emanation
Duration sustained up to 1 hour
You maintain a brisk performance that keeps allies on the move. You and your allies in the area can Hustle for the spell's duration, even though you are also Sustaining the Spell. You and your allies then become temporarily immune for 1 day.
Heightened (6th) You can Sustain the Spell for up to 2 hours.
Heightened (9th) You can Sustain the Spell for up to 4 hours.

So, what does the item do? Is it intended that it can extend cantrips like Inspire Courage, or is it simply broken and doesn't do anything?

[Cordell Kintner]

Future Proofing, it's definitely not "broken" as it works perfectly fine. Not every item needs to have an immediate use case.

[breithauptclan]

Hymn of Healing too.

No, that one isn't a cantrip. The item is specifically calling out cantrips only.

Which does seem strange.

[Squiggit]

Cordell Kintner wrote:

Not every item needs to have an immediate use case.

No, but it can feel bad when an item or feat references something that doesn't actually exist.

Future proofing is good, but I think Paizo could do better with having actual use cases on hand more often.

[pixierose]

until something comes up, I am going to just run it as being able to cast a composition cantrip and stride

[Tender Tendrils]

I had thought that it sustained the cantrip (hence extending its duration by 1 round) whether it can normally be sustained or not, but reading the sustain a spell action tells me that that technically doesn't work.

It might have been the intent however to sustain them anyway, and they just forgot about the wording in sustain that says it has to have a sustained duration. (note that "Cast a composition cantrip" is actually different to "Sustain a composition cantrip, even if it doesn't have a sustained duration normally" because the latter means it has to be the same composition - the latter also doesn't trigger stuff like counterspelling as a reaction or other effects that trigger of spell castings)