As an Unseen Servant is "shapeless", its size is not defined. The Alarm spell, however, relies on a creature's size (Tiny or larger) to be activated. Therefore, I'm not sure if an Unseen Servant, when commanded to walk through a location containing an Alarm, would trigger said Alarm or not. I would think it does, but I might be wrong (maybe the Unseen Servant's size value is "null"), hence the question.

Also, one of the two ways to receive an Alarm notification is mental. I'm wondering whether that notification can be customized, so that if the Unseen Servant crosses through Alarm #1, you can get a different "ping" than for Alarm #2. Again, I would think so, but it's better to verify (maybe it's always the same sound regardless).

Finally, I'm almost certain that if you go back and forth through an Alarm zone, you will repetitively get the "ping", but I just want to be 100% sure.


2 Answers 2


No, it still isn't a creature.

Unfortunately, the requirements for Alarm are clear in the spell description (as you stated) with the trigger requiring a Tiny or Larger creature. Because unseen servant is not a creature, it does not satisfy the requirements to trigger the Alarm (just like an illusion wouldn't trigger the alarm, either.)

As for customization of Alarm - that is up to discussing that with your DM and covers both the alert and the inclusion of Unseen Servant as a potential trigger.

  • 3
    \$\begingroup\$ A thief can use unseen servant to walk into your camp and take anything not secured... \$\endgroup\$
    – Protonflux
    Commented Jul 6, 2017 at 11:18
  • \$\begingroup\$ This is now out of date due to an errata \$\endgroup\$ Commented Dec 27, 2021 at 17:09
  • \$\begingroup\$ @AncientSwordRage Is it though? Having a size does not a creature make, methinks. \$\endgroup\$ Commented Dec 27, 2021 at 21:43
  • 2
    \$\begingroup\$ @thomas it can be outdated, even if the answer is the same. \$\endgroup\$ Commented Dec 28, 2021 at 0:18


Alarm (PHB p.211, emphasis mine):

Until the spell ends, an alarm alerts you whenever a Tiny or larger creature touches or enters the warded area.

Unseen Servant (PHB p.284, emphasis mine):

This spell creates an invisible, mindless, shapeless, Medium force that performs simple tasks at your command until the spell ends.

Alarm reacts to creatures; Unseen servant doesn't create a creature, so it can't trigger Alarm. Note that this has nothing to do with size.

  • \$\begingroup\$ Oh. Dammit. Right. Creature. Forgot about that. But...... If an Unseen Servant is holding an insect, then maybe... \$\endgroup\$
    – Gael L
    Commented Jul 5, 2017 at 16:34
  • \$\begingroup\$ @Mindwin Including unconscious ones ? \$\endgroup\$
    – Gael L
    Commented Jul 7, 2017 at 2:59
  • \$\begingroup\$ @Mindwin I seem to be getting on your nerves, which is not my intention. In hindsight, the real question I should have asked is "how can you know when an Unseen Servant finishes a task if you don't see/hear him?" Then people would have suggested probably better solutions than the one I'm attempting to validate above. I am deeply sorry for all the time you lost in dealing with me. But I wish you a good day. \$\endgroup\$
    – Gael L
    Commented Jul 7, 2017 at 14:06
  • \$\begingroup\$ @GaelL Probably not. Had you got on my nerves, I'd have walked away. I checked your profile, you are new to the stack as a whole, so I'd want to give you some pointers: the stack is bad for back-and-forth conversations like what you are trying to have. This is not a forum. You formulate a question, then get answers. Read more from one of our moderators rpg.meta.stackexchange.com/a/7271/11402 \$\endgroup\$ Commented Jul 7, 2017 at 15:14
  • 2
    \$\begingroup\$ @AncientSwordRage I’ve updated the quoted spell text to match the errata’d version. \$\endgroup\$
    – Marq
    Commented Dec 27, 2021 at 20:34

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