In fact I encourage that sort of thing. The player has participated in world-building without changing the game state to gain advantage, and maybe even has given me some hooks for the future.
What's the objection to the player changing the game state to gain advantage? Isn't that something that good players try and do?
What in the fiction lets me, as GM, know how difficult this task will be? I don't see anything, which makes any DC set entirely arbitrary -- it can't be grounded in either mechanics or the fiction. This is the first problem.
It's never been clear to me exactly how a 5e GM is meant to decide that some action has an uncertain outcome, or not, and how the DC is to be set. You seem here to be suggesting "objective" DCs - in the sense that the difficulty corresponds to or reflects (roughly) the in-fiction causal processes. Similar to a process-sim type game and unlike (say) Dungeon World or 4e.
When I wondered whether this might be a problem that you're seeing in the example I put forward, I wasn't very sure that I was right to do so. So it's interesting to me to see you affirm that it is a problem.
Doing this would priviledge classes that have Expertise mechanics
<snip>
if we're talking about introduction of challenge solving fiction this kind of success rate is unacceptable, not to mention the class disparities.
This one's not as clear to me. I thought the point of expertise and similar class features is to make those classes the best at resolving non-combat problems through non-magical means. So if they're better at this, is that really a bad thing? (That would depend upon a skill check and not just a CHA check being required - I'm not sure there's a skill that pertains to the sort of thing I suggested, but maybe that's a less significant point.)
there's a scope difference between introducing off-screen fiction (Uncle Bob told me about trolls) and establishing fiction present in the current scene.
I can see this. I'm less clear, though, where the 5e Basic PDF explains this difference and how it's fundamental to the play of the game. See further below.
The rules are clear on who gets to say what. The player gets to write a background during character creation. The DM helps him or her tie various elements of the background to the campaign, saying yes to the player's ideas if the DM can and suggesting alterations when the DM can't. This is laid out in the DMG under "Master of Worlds," as if the title alone was insufficient to tell us who gets to decide what.
During play, the player gets to describe what he or she wants to do. To that end, saying that the guard is Frances, an old friend, is a valid action declaration. But the DM is under no obligation to accept that the guard is, in fact, Frances or an old friend or both because the player has no control over this aspect of the game. Non-player characters are controlled by the DM, as per the chapter on NPCs in the DMG.
Looking through the 5e Basic PDF, this is what I find on pp 2-3 (sblocked for length):
[sblock]The Dungeons & Dragons roleplaying game is about storytelling in worlds of swords and sorcery. It shares elements with childhood games of make-believe. Like those games, D&D is driven by imagination. It’s about picturing the towering castle beneath the stormy night sky and imagining how a fantasy adventurer might react to the challenges that scene presents. . . .
Unlike a game of make-believe, D&D gives structure to the stories, a way of determining the consequences of the adventurers' action. Players roll dice to resolve whether their attacks hit or miss or whether their adventurers can scale a cliff, roll away from the strike of a magical lightning bolt, or pull off some other dangerous task. Anything is possible, but the dice make some outcomes more probable than others. . . .
In the Dungeons & Dragons game, each player creates an adventurer (also called a character) and teams up with other adventurers (played by friends). Working together, the group might explore a dark dungeon, a ruined city, a haunted castle, a lost temple deep in a jungle, or a lava-filled cavern beneath a mysterious mountain. The adventurers can solve puzzles, talk with other characters, battle fantastic monsters, and discover fabulous magic items and other treasure.
One player, however, takes on the role of the Dungeon Master (DM), the game’s lead storyteller and referee. The DM creates adventures for the characters, who navigate its hazards and decide which paths to explore. . . .
[T]he DM determines the results of the adventurers' actions and narrates what they experience. Because the DM can improvise to react to anything the players attempt, D&D is infinitely flexible, and each adventure can be exciting and unexpected. . . .
The play of the Dungeons & Dragons game unfolds according to this basic pattern.
1. The DM describes the environment. The DM tells the players where their adventurers are and what's around them, presenting the basic scope of options that
present themselves . . .
2. The players describe what they want to do. . . .
Sometimes, resolving a task is easy. . . . But [not always.] . . . In those cases, the DM decides what happens, often relying on the roll of a die to determine the results of an action.
3. The DM narrates the results of the adventurers' actions. Describing the results often leads to another decision point, which brings the flow of the game right
back to step 1.
This pattern holds whether the adventurers are cautiously exploring a ruin, talking to a devious prince, or locked in mortal combat against a mighty dragon.[/sblock]I find this rather reminiscent of Moldvay Basic. It's pretty clear as far as it goes. To me it seems to break down, though, as soon as we get into circumstances where the PCs are not strangers to the environment or the NPCs. If I'm playing my character, why do I need to the GM to tell me what I see in my own house? Or what my sister looks like?
Now it seems to me that there are some accepted cases in this general ballpark where
the player gets to establish the environment. Eg if a player says "I'm looking in my backpack for my rope", I think even at many 5e tables it will be accepted accepted that the player establishes that there is a backpack, and what's in it, in virtue of having written up an equipment list. Page 4 of the Basic PDF perhaps indicates this by saying "Each character brings particular capabilities to the adventure in the form of ability scores and skills, class features, racial traits, equipment, and magic items."
But then the character sheet at the end of the Basic PDF not only has an entry for equipment but entries for PC backstory and for allies and organisations. And chapter 4 begins by saying that "Characters are defined by much more than their race and class. They're individuals with their own stories, interests, connections, and capabilities beyond those that class and race define. This chapter expounds on the details that distinguish characters from one another".
So how - other than by way of RPGing/D&D tradition - is the player meant to appreciate that non-equipment but nevertheless intimate elements of backstory don't break the basic pattern of play in the same way that equipment lists do? The clearest hint I can find in the Basic PDF is on p 36, under the heading "Backgrounds":
The most important question to ask about your background is what changed? Why did you stop doing whatever your background describes and start adventuring? Where did you get the money to purchase your starting gear, or, if you come from a wealthy background, why don’t you have more money? How did you learn the skills of your class? What sets you apart from ordinary people who share your background?
This at least suggests that
adventuring is in fact something that occurs apart from, indeed divorced from, the PC's backstory. This is reinforced by the references on pp 2 and 3 to
towering castles beneath the stormy night sky,
dark dungeons,
ruined cities,
haunted castles,
lost temples deep in the jungle, and
lava-filled caverns beneath mysterious mountains. And by the statement on p 4 that
an adventure features a fantastic setting, whether it's an underground dungeon, a crumbling castle, a stretch of wilderness, or a bustling city. It features a rich cast of characters: the adventurers created and played by the other players at the table, as well as nonplayer characters (NPCs). Those characters might be patrons, allies, enemies, hirelings, or just background extras in an adventure.
Notably absent is the suggestion that NPCs might be friends, family or other people whom the PCs have connections with outside of the context of the adventure.
If adventuring is always or at least primarily undertaken in strange places among strange people, then the action declaration I suggested is never going to come up, which obviates the need to write a rule that deals with it.
Then it starts getting a little arcane.
