The Alexandrian

Numenera - Monte Cook GamesThe design ethos of Numenera is focused on providing the GM with a strong mechanical structure for making rulings while keeping those mechanics minimal so that the GM is free to make those rulings. That, all by itself, pretty much lands the system right in the middle of my sweet spot. But what really elevates the game to the next level – the thing that really makes it shine – is the GM intrusion mechanic.

Which is why it’s unfortunate that I’ve seen so many GMs struggling to grok the mechanic.

I understand where they’re coming from: I was skeptical about intrusions, too, until I saw them in actual play. They’re an unusual tool and it may break some of the expectations you have as a result of how RPGs typically work, but based on my experience it will be well worth your time to embrace them.


For those not already familiar with Numenera, here’s a brief overview of how the mechanic works: The GM announces that they are making an intrusion and hands the player whose PC is the primary target of that intrusion 2 XP. That player can either spend 1 XP they already have to cancel the intrusion (returning the 2 XP to the GM) or they can accept the intrusion, take 1 XP for themselves, and give 1 XP to another player.

The core functionality of the GM intrusion is that it allows you to make things worse than the mechanics of the game would normally suggest. An easy example is having a PC drop their weapon: If you’re playing a game that doesn’t have an explicit fumble mechanic for that, it would be really unusual for a GM to announce that this happens on a failed attack roll. It would be even more unusual for a GM to decide that it happens on a successful attack.

But that’s what the GM intrusion allows you to do: You thought it would be cool for the PC to hit the mammoth-saur with his axe so hard that the axe got stuck in the creature’s thick hide and wrenched out of his hands. In any other game, this would usually cause the players to disconnect from the game world and be wrenched into the metagame because the GM is “breaking the rules”. But the GM intrusion mechanic not only lubricates this interaction (allowing the player to stay focused on the game world), it also includes a feedback mechanic by which the player can say “no, you’ve gone too far, I reject the intrusion”.


Some of you may now be pointing your finger in horror and crying out, “Dissociated mechanic!” And, yes, that’s true. The mechanics of XP spending in Numenera is very similar to the use of fate/luck points in other systems and they’re tied directly into the intrusion mechanic.

But as I’ve mentioned many times in the past (and, most notably, in the Brief Primer on Dissociated Mechanics), it’s not the end of the world for an RPG to include some dissociated mechanics as long as those mechanics are providing a valuable function.

In the case of GM intrusions, the function of liberating the GM to take huge creative risks while being “protected” by a safety net which allows the players to seamlessly rein them in if they go too far is absurdly valuable.

It should also be noted, for those who are particularly allergic to dissociated mechanics, that GM intrusions are incredibly flexible tools which are used entirely at the GM’s discretion: You can use them all the time, you can use them rarely, or you can use them never. More importantly, the nature of each intrusion is entirely up to you. That means you can make them as associated or dissociated as you want: It’s very trivial, for example, to only use intrusions which a PC could avoid or negate through the actions they take.


This ties into something that’s really important to understand about GM intrusions:

The primary purpose of an intrusion is NOT to punish the players.

Intrusions are actually doing the exact opposite of that. In fact, if you’ve ever had the experience of having a really cool idea (like a character’s axe getting stuck in their opponent) and then rejecting it because it’s kind of a bullshit move and it feels unnecessarily punitive to your players… well, GM intrusion greases the wheel for it.

But intrusions aren’t just a method of injecting awesome into your campaign. Of equal importance is their other primary function:

Use GM intrusions to handle outright shortcomings in the rules.

Rather than provide laborious technical detail, Numenera trusts the GM to make specific rulings from generic guidelines. But it also realizes that useful abstractions can frequently give rise to illogical situations when applied to the details of specific situations: GM intrusions provide a useful omnitool for restoring logic.

An example given in the rulebook is a PC who decides to turn his back on an armed opponent in order to raise a ladder into position: According to a strict interpretation of the rules, there’s no reason that the PC can’t do that (he has initiative and so he takes and completes his action before the NPC). The GM, however, recognizes that this doesn’t make sense in the specific context of the action being proposed, so he uses a GM intrusion to give the NPC a free attack on the PC.

Couldn’t the game have included a full suite of mechanics for “attacks of opportunity” or something like that? Sure. But what do you do about the next corner case? And the next one after that? Just keep adding more rules? Pretty soon you end up with a rulebook that looks like Shadowrun 5th Edition. There’s nothing wrong with that, per se, but Numenera is giving you a different way of dealing with the problem.


Because GM intrusions are such a flexible tool, they can also be used as a narrative control mechanic. What’s interesting about their use in this context is that the GM is still the ultimate arbiter of when the intrusions will be used, which means that the GM can run a very traditional game while opening up specific arenas within the game world for negotiation.

An example frequently used in the Numenera rulebook is the appearance of unexpected reinforcements: The GM uses an intrusion and two more chirogs drop out of the leafy canopy above you!

Let’s break down the options here:

  1. The GM could decide NOT to have any reinforcements up.
  2. The GM could decide that the two chirogs are DEFINITELY there and the players have no say about it.
  3. The GM could decide that the two chirogs MIGHT be there and use a GM intrusion to negotiate their arrival with the players.

A purely traditional RPG only offers the first two options (and those options still exist in Numenera); but the intrusion mechanic offers the third.

And this third option – the narrative control option – can really be pushed even further than the rulebook takes it: Any element of the game world that you’re willing to open up to negotiation with your players can be slickly handled through the simple interface of the intrusion. Is their best friend secretly betraying them? Has the king been replaced by a technological doppelganger? Are the rat things actually friendly and misunderstood (instead of vile and evil)?

As these examples also demonstrate, it’s not necessary to think of an intrusion as a singular point in time, either: They can have wide-ranging and irrevocable implications for the future. Or, alternatively, seamlessly retcon the past with terrible revelations.


Perhaps the most common use of the GM intrusion at my table is the “uber-fumble”: Wow, it sucks that you failed that check. Here, lemme make it a little bit worse for you.

Cranial Slugs: Not Even OnceNotable examples from my last few sessions include:

  • You try to dodge out of the way of the club, but you duck the wrong way. It slams into your chest, lifts your from your feet, and sends you hurtling backwards… directly through the dimensional rift.
  • The psychic assault emanating from the cranial slugs burrowing into your skull suddenly forms a horrific neural net that short circuits through your synapses. Take 3 Intellect damage… and the creature has taken spastic control of your limbs. You’ll attack Sheera next round.
  • Your razor wing hurtles towards his face, but his hand snaps up with lightning speed, snatches it from the air, and whips it back towards you. Give me a Speed defense check.

I find that these moments provide spikes of intensity and interest that can break up the normal cycle of a combat: Whenever the pace of an encounter seems to be lagging or has settled into a predictable cycle, the use of an intrusion immediately shakes things up. (Using unusual actions and events during a combat encounter is just good advice in general, of course, but intrusions really let you dial the intensity up to 11.)

One of the unique ways you can leverage intrusions to accomplish this, however, is by merely threatening the intrusion before the dice are rolled. This technique is particularly effective if you’re using the Numenera XP cards: As the player prepares for the roll, simply grab two XP cards and hold them up for the table to see. The message is clear: If Heather fails her roll, something extra horrible is going to happen.

This is a form of metagame special effect: By raising the stakes of the roll, you focus the table’s attention and passion on the die roll. This works particularly well in Numenera because the modifiers to a task are all applied to the difficulty: By the time you roll the dice, you know exactly what number needs to appear on the face of the die for success. When the die lands, there is an immediate and explosive release of all the tension built into that roll (one way or the other).


The Numenera core rulebook recommends one GM intrusion per player per session.

If that works for you, great. In practice, though, I’ve found that I’m using them about three times more frequently than that. I don’t really have a specific goal of using X number of intrusions per session, of course. I just use them when it feels right (which usually means whenever I’ve got a good idea).

By the same token, you don’t want to overuse your intrusions, either. Only use an intrusion if you’ve got a really awesome (or really horrible) idea. You want your intrusions to mean something.

The other thing you should be cautious of if you find yourself using lots of intrusions is the accumulation of XP: If your players are frequently spending XP to reroll dice, purchase short-term benefits, and the like you probably won’t run into any problems. If you end up with a table which is consciously hoarding their XP and refuse to spend it on anything except character advancement then plenteous intrusions can make the problem worse.

(In general, though, hoarding XP in Numenera produces a sub-optimal experience in any case. So you should try to figure out how to get your players to use XP in the way the game intends: That might mean that you should be doing a better job of offering awesome short-term benefits to encourage XP expenditures. Or it might just mean talking to your players and making sure they understand the opportunities they’re passing up. Or, as the rulebook suggests as an alternative solution, you could also just impose a ratio of short-to-long-term XP expenditures.)


The final word of caution I would give about the use of intrusions is this: Don’t negate success.

The rulebook talks about using intrusions in order to force a task check even when the character would normally succeed automatically. In my opinion, such intrusions should be used very sparingly. And what you should never do is take a successful die roll and turn it into a failure. It’s cheap and it’s frustrating.

To be clear: It’s okay to complicate success. Just don’t negate it.

If their sword gets stuck in the mammoth-saur, the mammoth-saur still gets hurt. If they shoot the rope holding up the numenera device creating an interdimensional portal, the device still falls (even if the intrusion reveals that it’s going to fall on top of them). If they succeeded in following the bad guy’s tracks, they still succeed in finding the bad guy (it just turns out he’s laid an ambush for them). And so forth.

I suppose this can probably be broadened into a general principle:

Your players should hate your intrusions, but they should love to hate them.

Numenera XP Cards - Monte Cook Games

Share on TumblrTweet about this on TwitterShare on StumbleUponShare on FacebookShare on RedditShare on Google+Digg this

17 Responses to “Numenera – The Art of GM Intrusions”

  1. stm says:

    I like this mechanic. It’s quite similar to Fate Points and I happen to like Fate as well. But how would you suggest to integrate this into other games,, say D&D? Action Points spring to mind, but would the Numenera’s XP mechanic work well with D&D (players)?

  2. C'mon says:

    Would you hurry up and review 5e already?

  3. d47 says:

    You are making me want to try Numenera and the other new Monte Cook game. That mechanic sounds fun!

  4. John says:

    This is a pretty neat mechanic, and your article does a nice job of explaining its utility. I don’t know the system, so can you give some context to how valuable 1 xp is to a PC? Or put another way, how big of a carrot does the system hold out in order to entice players to accept the intrusion?

  5. John says:

    This is a pretty neat mechanic, and your article does a nice job of explaining its utility. I don’t know the system, so can you give some context to how valuable 1 xp is to a PC? Or put another way, how big of a carrot does the system hold out in order to entice players to accept the intrusion?

  6. Brotherwilli says:

    GM Intrusions have been one of the highlights of my Numenera games; I think the advice you have here is excellent. If I may share a few of my favorite moments with GM intrusions:

    – A character emerges from a teleporter, with the rest of the party behind him. As the teleporter recharges, he stops to investigate it to see if he can figure out how it works. He is able to do so, but an intrusion causes the teleporter to relocate, separating the party.

    – A character went into a strange tube to be cleansed of an alien disease. While in the tube, an intrusion causes it to rework his DNA in subtle ways, greatly lengthening his arms.

    Justin, do you use GM Intrusions to further plot points frequently? For example, in the adventure The Nightmare Switch, an intrusion is taken to let one PC receive a special dream at the outset. This dream is crucial to an expedient resolution of the adventure. That struck me as odd, because it’s not a complication so much as a key element.

  7. Brotherwilli says:

    @John: The game has a lot of uses for XP. One XP can be used to refuse an intrusion or re-roll a die. Two XP can be spent for a short term or medium benefit (such as having knowledge of a specific mountain range, or cobbling together a device that allows you to breath underwater for a limited time). Three XP can be spent to gain a permanent but specific benefit (gain a modest bonus to skill checks in specific situations, gain a contact, etc. ).

    Four XP can be used to gain a character advancement that improves their skills, abilities, or stat pools. This is the “main” advancement mechanism. A character selects from a list of potential character advancement options. When they have selected four options, they advance to the next tier. Characters start at Tier 1, and max out at Tier 6.

    So, in short, it takes 16 XP to advance to the next tier, but because of the character advancement rules, PCs gain a lot as they work towards the next tier.

  8. Kinak says:

    The uber-fumbles are great!

    Good advice all around. I feel much more comfortable with the idea of running Numenera having read it.


  9. JOjo says:

    That’s a horrible metagaming mechanic. But thank you for bringing it to my attention. I will not be purchasing Numenera based on that alone. It is way too immersion breaking.

  10. Justin Alexander says:

    @JOjo: It seems weird to reject an entire game because of one optional rule which, as I noted, you can choose to use or not use to suit your taste. It’s like saying you’re not going to play D&D because it has unicorns in it, when the more obvious solution is to simply not use unicorns in your campaign world if you don’t like that sort of thing.

    This is also an excellent example of why I don’t use the word “immersion”. Because the actual effect of this mechanic is, in fact, to deeply immerse the players into the game by drawing them into the experience. For many players, the mirroring of the tension within the game universe with the tension built into the intrusion mechanic also serves the function of making them feel more fully immersed in the experience of their character. (On the flip-side, the dissociated mechanic of choosing when to use an XP to refuse an intrusion or re-roll a die roll can disrupt the immersive process of a player who wants all of their decision making during the game to be exclusively dedicated to their character’s decision-making process.)

    The word really does mean nothing in the roleplaying industry.

    @John: Brotherwilli has done a pretty thorough job answering your question. In my games I think probably 90% of the XP gained from GM intrusions ends up getting plowed back into rerolls (often as a result of dealing with other GM intrusions). I keep meaning to do a more accurate accounting of that, but there are better things for me to be paying attention to while running the game. 😉

  11. C'mon says:

    A large part of the reason why I read your site religiously is because of the insight you provided on how incredibly awful 4e turned out, and wrote the defining essay on dissociated mechanics in the process.

    Are you waiting on the DMG or something? They’ve already got an adventure published.

    Attacks of Opportunity no longer glue characters together.

    Skill challenges are history.

    Most feat taxes are gone (Dex to attack and damage, move-attack-move, etc. are core abilities for everyone). Feats are an optional rule, allowing new players to stick to what they know and not be punished for it, since the feats replace an ability boost each time but pack a whole lot more (two to three times what a 3.5 feat did) into each choice. System mastery means an ability to do more complicated things, and is not a requirement to play the game at all.

    Vancian casting has had some wrinkles removed (playing a wizard or cleric no longer requires as much daunting, beginner-repelling paperwork), and caster power on the whole has been scaled back relative to other classes. Casting doesn’t provoke attacks of opportunity by default, but getting hit while casting can still shut you down, and a whole lot more spells now require concentration.

    Eldritch Knight and Arcane Trickster are now core options for single-classed fighters and rogues.

    The optional multiclassing rules allow casters to branch out without suffering all that much, though still taking a hit in power. Also, taking levels in two casting classes with the same key ability at once no longer gives you effectively unlimited spells per day.

    Keeping track of countless circumstantial buffs is now “does the roll have advantage or disadvantage? No? Moving on…”

    Using a grid is now considered an optional rule. HOLY GOD, IT’S NOT A PLOT TO SELL MORE MINIATURES!

    Polymorph is fixed, now using the polymorph subschool rules from 3.5 and NO NATURAL SPELL, PERIOD. WOOHOO.

    The Inspiration mechanic allows rewards for good roleplaying in a way that’s less metagamey than RP XP. It also means picking a background for purely build munchkinism purposes locks you out of a meaningful aspect of the game.

    Backgrounds provide useful guides for any new players suffering from “writer’s block” on roleplaying, and the skill proficiencies make them a required part of character creation. No longer will munchklns create a ludicrous combination of races, classes, and feats and complain when asked for a backstory for the collection of numbers on their “character” sheets.

    The skill system now provides bonuses to ability checks when used to accomplish certain goals (training in Arcana now provides bonuses on Intelligence checks related to magic and spells, for example). This means that your infamous wagon wheel example (where you had to improvise an ability check) no longer feels out of place or unsupported, but is instead encouraged by the rules. And if you feel the need for added simulationism or “more structure,” the rebalanced math means that the 3.5 skills and DCs can be plopped in with almost no modification, and as an added bonus, ridiculous builds like the Diplomancer are no longer a concern.

    Since sources of bonuses are far less common, the rogue’s status as best party sneak never feels in jeopardy, but since level is still factored into the check and favorable circumstances typically translate into “roll twice and take the highest”, not even the cleric is truly locked out of trying to sneak. Same with the rogue trying to stanch a wound or repel a vampire.

    At least give it a “first impressions” article. There’s a free PDF.

    If you find problems, I’d love to hear about them.

  12. Justin Alexander says:

    @C’mon: The only thing I can really tell you about D&D 5E at the moment is that nothing in their marketing nor the reviews I’ve read has convinced me to drop everything else I’m doing and check it out.

    “But there’s a free PDF!”

    The primary limitation here is not money. It’s time. I’m currently running a 3.5 campaign, a Numenera campaign, and a Trail of Cthulhu campaign. I am also running rotating one-shots of Technoir, Numenera, The Strange, and Eclipse Phase. I’m currently scheduled to game 1 day out of every 3 in September and it’s likely that I’ll be adding 2-3 more sessions before the month is done. I’m also actively researching several other game lines in an effort to get freelance work lined up.

    Although I’m currently blessed with a lot of opportunities for gaming, I still have a limited amount of time to dedicate to RPGs. So D&D 5E would need to make some sort of strong case for why I should carve out the time to read 100+ pages of rules mechanics. (The strongest case would be convincing me that I would actually play it at some point.) 5E hasn’t done that yet.

    The strongest tickle I’ve had so far was actually a desire to check out Hoard of the Dragon Queen. But that only resulted in me discovering that WotC is still allergic to e-books, which roadblocked my interest.

    None of which is to say that I will never look at 5E. It’s almost certain that I will at some point. It just isn’t a priority for me at the moment.

  13. Alphastream says:

    I appreciate your article, and it does give me new ideas. I’ve so far had problems getting GM Intrusions to work. There are three main reasons:

    1) Breaks immersion.
    During a typical RPG game I might decide a fight is too easy, so the floorboards suddenly break upwards and more zombies join the fight. I make the call as DM, given what I expect will be fun at the table. It happens exactly when I/we want it to, and it is seamless. It can seem planned, because the players don’t know if I’m making this up or had counted on doing this.

    During Numenera, I felt like every time this happened I had to stop, offer the player XP, and engage in this non-in-the-moment discussion. Which, 99% of the time, was a “yes” anyway. Then I bring in the zombies, but now every player knows this is a contrived interjection.

    2. XP is wonky.
    We find XP to be fairly wonky. PCs need a fair amount to “level”, and they want the power-ups provided by leveling, which all requires XP. This makes it a real disincentive to say “no” to an intrusion. You have to really want to say no to something to say no. And, generally, when would a player do this?
    – It is unfair
    – It would result in PC death
    – It seems very un-fun

    But, realistically, isn’t a good DM going to pretty much always choose something relatively balanced (some risk, sure, but not ridiculous… because why would a player say yes to a likely death… and why would a DM insert such a thing?)? So, if it isn’t unfair and is fun, and if losing XP is bad… what’s the point of the the whole immersion-breaking negotiation?

    To be fair, I do see some places. As with FATE, a GM can feed off of a PC’s backstory. I might decide that the NPC they love could turn against them based on a misunderstanding. It isn’t any risk issue, it’s a visceral personal thing and the player could dig it or not depending on the story they have in their mind for their PC. It can just feel wrong, _right now_, for a breakup with that NPC. But, that’s really not what the GM Intrusion system showcases as examples.

    3. Seems more unfair than it really is.
    I had trouble with what the negotiation brings to the table. It seems to indicate to the player, “hey, the DM might be messing with you. This has a reward or cost, so do the math and determine if you come out ahead.” It isn’t just, this happens, get a reward, but an actual trade/barter, and in my play experience this made GM Intrusions undergo some scrutiny. The player pauses (again, breaking immersion) and weighs the pros/cons (even when it is a balanced non-risky fun thing), and it overall has a far more negative feeling than it should. And, this experience was with a group I really know well and who I have DMed countless times. They are used to me changing things… but suddenly I’m calling it out and the mechanic seemed to force this analysis of pros/cons… why?

    Gm Intrusions remain one of the parts of the system I just couldn’t get to work, despite trying various things and purchasing the additional Intrusion supplement. I have no problem making my own changes and I’ve enjoyed aspects in FATE.

    Thoughts? Am I missing something obvious?

  14. Justin Alexander says:

    (1) I don’t actually use the “reinforcements as intrusion” mechanic, for basically the reasons you describe here. As I mentioned in the essay, this is one of the things I think is great about the intrusions mechanic: Its use (or non-use) is entirely up to the GM. So if you find that there’s a particular type of intrusion that doesn’t work well for you or your players, you can just choose to not use that type of intrusion any more.

    For similar reasons, the refusal of the intrusion is almost always narrated into the game world at my table. So if I offer an intrusion in which a monster sprouts an unexpected pseudopod that trips up a character rushing toward it as an off-turn action, the refusal of that intrusion doesn’t cause the pseudopod to vanish: Instead, the XP is paid and the character leaps over the pseudopod while completing their charge. (Or whatever.)

    (2) The key thing for me is that intrusion allows me to expand the boundaries of “fair” and push the boundaries with things that I think will be fun but worry that the players might not.

    For example, if I was running D&D I would never have a monster sprout an off-turn tripping pseudopod unless it had that ability in its stat block. I wouldn’t consider it fair play even if I thought it might be fun or entertaining for that moment to happen. The intrusion gives me permission to do something that isn’t “fair” (in the sense of honoring a strict interpretation of the rules of the game) and simultaneously let’s the player say, “I don’t agree that this moment of the bad guy gloating as we ineffectually try to reach him is a cool moment.”

    (3) I suspect that intrusions will not work well if you have a highly adversarial relationship with your players. If you (or your table) are thinking of the intrusion as “the GM wants to screw you” they aren’t going to work well. Instead, the use of an intrusion should be saying, “I’ve just had an awesome idea. What do you think?”

  15. Alphastream says:

    Those are good thoughts, thanks. I especially like the idea of narrating the denial.

    On the tentacle bit, I would absolutely do that in D&D, but never to screw the players. I know D&D really well… well enough to know that sometimes an encounter just doesn’t do what I meant for it to do. If it was supposed to feel really exciting, swarm of tentacles everywhere, and backs-against-the-wall fury, and it wasn’t… I would absolutely add an off-turn tentacle attack. The addition isn’t me being unfair, but rather correcting the encounter to what it was supposed to provide. It was going to be boring, now it will be more fun. I’ve been making these kinds of changes for years. That doesn’t mean I don’t believe in stat blocks – I do. But, I know them well enough to know they don’t always do what they were meant to do. Correcting on the fly is something I see as a DM’s core duty. If it isn’t fun, change it so it is.

    I need to experiment more to make GM Intrusions make more sense in my style of play, for sure. Thanks for the help!

  16. Buhallin says:

    VERY late to the party on this one, but I just started GM’ing Numenera for the first time, and having come across this I thought I’d offer a few of my early thoughts. A few of the reasons I like intrusions, personally, that I don’t think have been mentioned:

    1. They make the GM think about what they’re doing to the players. The point above focused on the negotiation of refusal, but I think the GM’s consideration of whether to give the XP in the first place is just as important. “I might typically do X to a character, but is it worth accelerating the XP curve?” I think this is good for GMs because it gets them thinking about how the intrusion benefits what they’re doing. It places value on the GM’s choices, which is very rare.

    2. I think a system like this is very helpful for more abstract systems. Say you have a column in a room during a fight, which collapses. Who’s standing near/under it? If you’re playing on a grid map, everyone knows. If you’re using a more abstract system, it becomes far more of an issue. Is anyone under it at all? Largely up to the GM… Same thing applies to many other efforts to gloss bookkeeping. Who runs out of ammo if you’re not counting bullets? etc. More abstract systems need something to govern this so it’s not just the GM being mean. I’ve played a lot of the FFG Star Wars lately, and it handles this with the Despair results, making it a factor of (mostly) luck. Intrusions do it by basically paying the victim. Not only does a little XP take the sting out, it convinces the player that the GM thinks it’s worth it (See #1).

    Overall, loving both the world and the system so far, and intrusions are a big part of that.

  17. Justin Alexander says:

    Great points, Buhallin!

Leave a Reply



Recent Posts

Recent Comments