In the Numenera Corebook, rules for expending XP (p112 in particular) state that one can spend 3 XP to obtain a long-term benefit, in particular to craft an artifact:
Artifact: The PC creates an artifact that has a power of his
choosing. If the item is fairly simple, the GM can skip the crafting
details and just say that after a period of time, the PC creates it.
For an item that significantly alters gameplay—granting the character
vast telepathic powers or giving him the ability to teleport at
will—the GM might require difficult rolls, a considerable amount of
time, and rare, hard-to-find components and materials
On the other hand, a few pages earlier (p109), the corebook states that when players find or are given an artifact, they should be awarded XP equal to the artifact level (minimum 1XP per player):
Artifacts: When the group gains an artifact, award XP equal to the
artifact’s level and divide it among the PCs (minimum 1 XP for each
character). Round down if necessary. For example, if four PCs
discover a level 5 artifact, they each get 1 XP.
Now, one of my players chose the "Crafts Unique Objects" focus, and has told me he's very interested in crafting "a motorcycle". This would have to be an artifact, as I see it. It would take him some time to craft, and be difficult, since he's tier 1. But my question is about the interaction of these two rules. Should I take the 3 XP from him and then pass the resulting XP to the group? Should it work some other way? I didn't see anything in the focus (for tier 1) that would contradict this.
Best Answer
Note in advance that there is no published reference to exactly how this should be treated (that I can find) - this is based purely on the otherwise published intent of the experience system of the game (and how I interpret it). Also note that the Numenera core rulebook as written does feature many ambiguous and seemingly unpolished rules, so are often open to different interpretations.
Discovery, not possession, leads to advancement
The core of Numenera's experience system is the idea that discovery leads to character advancement, thus finding artifacts, discovering secrets of past worlds, and similar forms of increasing knowledge leads to character advancement (as detailed on pages 108-109).
In comparison a player crafting a specific artifact of their own devising is not discovering something new, they are expending effort to create an item that they have considered and planned before beginning the creation process.
Discovery is also something that requires considerable time and toil from the players - just as they should not be awarded experience for walking into the nearest store and buying an artifact, they also should not be awarded experience for something they can do from the safety of a workshop.
Even for significantly powerful items that may require adventuring to obtain rare components, there may be some experience gain in the process, but the item itself is the reward the players are seeking, thus they should not directly gain experience from the creation of the artifact.
XP for nothing
Consider also how broken it would be for a player to craft a level 1 artifact of their own design, and everyone in the party thus gains 1XP. As stated on page 109 PCs gain a minimum of 1XP each for discovering an artifact, thus a level 1 artifact is still worth 1XP each (although the same section states to round down if necessary, so depending on your interpretation 3 players may earn nothing from discovering level 1 & 2 artifacts). Either way this would still become a very cheap form of advancement, but creates an otherwise bad gaming experience without the GM taking action to stop it.