tgame/docs/18-expedition-engagement.md

Expedition Engagement & The Latent Party Matrix

Continuation of 2026-05-12 brainstorm. Extends 04-expeditions.md and builds on 17-foldins-2026-05-12.md. Loose design notes, not a spec.

Premise

The Steam pivot (17-foldins) reframed pacing from mobile pop-ins to in-session minutes. A 5-min mobile pickup didn't need a spine — the pop-in was the spine. A 30–90 minute Steam session does. The session needs an arc that opens, escalates, resolves.

The expedition is the session spine. A run is the contained arc: launch → orchestrate → recall → wind down. Everything else — crafting, hire pool, patron orders — happens around and during the run, but the expedition is what gives the session shape.

The concern that prompted this work: "is there enough to actually do in this game?" Diagnosis — "always something shiny" was sized for the entire 5-min interaction. For a Steam session, the shiny-pulse is texture, not structure. The expedition has to do the structural work.

Sealed-run principle

Once an expedition launches, the player cannot reach into it. No mid-flight gear swap, no resupply courier, no mid-run provisioning, no remote orders. The party is in the field on its own; the player is the home base.

Engagement lives in the book-ends and the event stream:

1. The Brief — pre-flight planning, party assembly, provisioning, routing
2. The Stream — in-flight event responses (decisions only, no material interference)
3. The Report — post-flight debrief, haul triage, narrative compile

This rule is intentional. In-flight intervention destroys the morning-after test (cultivates compulsive check-ins) and trivializes the planning surface (any pre-flight mistake is recoverable mid-run). Sealing the run forces commitment, makes planning matter, and respects the player's time.

Three engagement surfaces

1. The Brief

Pre-flight is a real puzzle, not a checkbox. Working surfaces:

• Routing within the zone. A destination isn't a single picker. Each zone has paths — Ravenwood has river road (slow, safe), ridge cut (fast, exposed), old culvert (capability-gated: needs torch + Lettered). Different paths bias different material distributions, event tables, and risk profiles.
• Declared goal. "We're after moonpetal" / "open hunt" / "patron job" / "discovery run." Biases event resolution and drop weights toward the goal. The party plays toward what you told them.
• Risk dial. Cautious / Standard / Aggressive. Modulates how the party auto-resolves events the player ignores. Aggressive Dora pushes into the cave-in; Cautious Dora retreats. Distinct from trait disposition — this is party temperament for this run.
• Provisioning as commitment. Carry capacity is shared between outbound provisions (rations, kits, consumables) and inbound haul. Bring 2 extra rations = stay longer, but 2 fewer slots for return loot. Real trade-off.
• Party-comp synergies that read. Tooltip-surfaces both known synergies (from Library entries earned through play) and budget shape. The build takes shape visibly as the player slots members.

2. The Stream

In-flight events are the only interactivity, so they have to work harder than flavor pings. Event class taxonomy:

• Flavor pings (~70%) — zero-choice texture. AI-batchable. Carry tone and party-chemistry signal.
• Light decisions (~20%) — binary, low stakes, fast.
• Capability-puzzle events (~5%) — gated on party composition. "Cave-in. Strong clears it; Lettered reads the inscription; Lucky finds the cache. Your party has Strong only — push through or detour?" Party comp retroactively matters.
• Chain events (~3%) — multi-stage. Event 3 plants a clue; event 7 calls back; event 11 closes. A single thread stretches across the run.
• NPC encounters (~2%) — recurring named strangers across runs. Build relationships that pay off in future expeditions or patron emergence.

Critical: events shape the report, not just the loot. Choices ripple into the post-run library entry, into trait shifts, into character titles earned. Decisions echo.

3. The Report

Debrief is a verb, not a popup:

• Triage sort. Haul drops as a pile to sort — stockpile / sell-queue / patron-order / gift-to-engineer. Some materials are time-sensitive (fresh moonpetal sells higher, ages in-session).
• Story compile. Run produced N notable moments. Player picks which becomes the Library entry — editorial agency over the narrative record.
• Trait evolution moment. "Dora was tested in the cave-in. Mark her: Tested, Scarred, or let it pass?" Small post-run decision that shapes roster development.
• Patron payoff. If the run filled an order, the handoff is its own beat — Aldric pleased/displeased, rep shifts, named NPC reacts.

Optional rhythm: legs

Single in-flight interactivity that respects the sealed-run principle: between-leg check-ins.

An expedition has discrete phases — Approach → Subzone A → (optionally) Subzone B → Return. Inside a leg: pure event stream, auto-resolve baseline. Between legs: party radios in with a real decision-gate. "We've cleared the foothills, hauling 6 ore. Push into the deep pit (Tier 4, better drops) or beat retreat?"

The player is answering a check-in, not reaching into the run. The party's already there; the player is choosing the next leg's character. FTL-map shape inside one expedition. Adds rhythmic decision points without breaking the seal.

Trade-off: doubles authoring surface (per-leg event tables). Working position: include legs but keep most expeditions to 2 legs (Approach + Single Subzone + Return); 3-leg expeditions are higher-tier opt-ins.

Token-budget party model

A party isn't just who's there — it's the shape of the budgets those people contribute to. Small World–inspired: each combination plays differently because the token flow is different.

Working set of budgets:

Budget	What it spends on	Contributors
Reach	Legs unlocked, depth into zone	Scouts, Halflings, light-encumbrance, certain consumables
Stamina	Each event drains; party retreats when empty	Steady, Brave, healers, ration prep, alchemy supplies
Carry	Haul capacity	Strong, pack animals, saddlebags, Bag of Holding
Insight	Unlocks capability-puzzle events (Lettered, perceptive, lore)	Scholars, Lettered trait, certain heritages
Standing	NPC encounters, trades, negotiations	Merchants, Charming, faction-tagged characters

A party's build is its budget shape. Same headcount, different shape, different game. The number on the screen matters less than the readability of the shape — players should see what kind of party this is at a glance.

Builds as a real noun

Budget shapes have natural archetypes. Players name them in their heads:

• The Foothold — Steady gatherer + Brave defender. Tall Stamina, short Reach. Predictable run.
• The Wedge — Halfling scout + Lettered scholar. Tall Reach + Insight, almost no Carry. Library-hunter.
• The Plunder Run — Greedy gatherer + Drunk beastmaster + soldier. Tall Carry, weird Stamina, rich event texture.
• The Quiet Path — Stealth-tagged pair. Skips encounter events. Low ceiling, high consistency.
• The Wraith Detail — Necromancy-aligned trio for Ravenwood. Death-resistant in that biome; would die in a meadow.
• The Mentor Run — Master + Apprentice. Slow, but apprentice gains trait shifts faster. Investment, not haul.

These aren't designer-authored archetypes shipped with the game. They're emergent shapes players discover and name. The system has to produce them, not enumerate them.

The hire pool constrains exploration (you don't pick the ideal party, you pick from who applied) — which forces players into combos they wouldn't have chosen voluntarily. That's where surprise lives.

The latent party matrix (MBTI-adjacent)

This is the structural core. A four-axis latent model that determines a party's chemistry — never exposed to the player, always shaping outcomes.

Why this works

A 4-axis matrix is the smallest authoring surface that produces emergent character chemistry at scale:

• 16 types from 4 binary axes — vastly more compressible than authoring pair-by-pair (6 traits × 6 = 36 pairs before heritage/class/gear)
• Each axis is independently meaningful — author behavior per-axis, compositions inherit naturally
• AI batches cleanly along axes — "write events for high-Curious, high-Wandering, conflicted-Engagement parties in Burned Hills" is a tractable prompt; "write events for Brom + Miles" is not
• Player folk-knowledge tracks coherence, not labels — humans notice patterns without naming them. "Brom and Dora always find weird stuff" is exactly what happens when output filters through a consistent latent space

The fact that it's never surfaced is what makes it work. The moment players see "Brom: ENFP," the magic is gone — optimization replaces mythology. Hidden, it stays folklore.

MBTI-adjacent, not literal MBTI

The four-axis discipline is what we want. The I/E/S/N/T/F/J/P labels carry corporate-workshop baggage and validity debates we don't need to inherit. Internal labels for tgame, mapped roughly to the MBTI shape:

Axis	Pole A	Pole B	MBTI rough-equivalent	What it modulates
Engagement	Bold (+) ←→ Withdrawn (−)	E / I	How often events fire vs. get sidestepped
Lens	Concrete (+) ←→ Curious (−)	S / N	Drop bias — mundane resources vs. unusual/lore/cursed/whimsical
Disposition	Pragmatic (+) ←→ Sentimental (−)	T / F	Auto-resolve defaults — takes the loot vs. rescues the captive
Tether	Disciplined (+) ←→ Wandering (−)	J / P	Route adherence vs. tangent-following

A party type is the 4-tuple of axis tilts. 16 archetypes if axes are treated as binary; in practice the axes are continuous and the type is the shape of the vector.

The math

Each character has a latent 4-vector, computed from heritage + traits + class. Each axis ranges roughly [−1, +1].

# Character vector composition
character.vector = clamp(
    heritage.bias_vector
    + sum(trait.modifier_vector for trait in character.traits)
    + class.bias_vector,
    min=-1, max=+1
)

Example: Brom — Human, Brave, Soldier

Component	Engagement	Lens	Disposition	Tether
Human heritage	0	0	0	0
Brave trait	+0.5	0	+0.2	0
Soldier class	+0.3	0	0	+0.2
Brom	+0.8	0	+0.2	+0.2

Example: Dora — Halfling, Lucky + Cautious, Gatherer

Component	Engagement	Lens	Disposition	Tether
Halfling heritage	−0.3	+0.2	0	−0.4
Lucky trait	0	+0.4	0	+0.1
Cautious trait	−0.4	0	0	+0.2
Gatherer class	0	+0.1	−0.1	0
Dora	−0.7	+0.7	−0.1	−0.1

Party aggregation

Per-axis combination:

for each axis:
    member_values = [m.vector[axis] for m in party]
    party.vector[axis] = mean(member_values)

    if all(v >= 0 for v in member_values) or all(v <= 0 for v in member_values):
        party.conflicted[axis] = False
    else:
        party.conflicted[axis] = True

Important: simple averaging produces muddy mid-types and erases chemistry. The conflicted-axis flag preserves the interesting case — when members pull opposite directions, that's not a wash, that's a distinct latent state with its own event class.

Example: Brom + Dora party

Axis	Brom	Dora	Mean	Conflicted?	Reading
Engagement	+0.8	−0.7	+0.05	Yes	They push-pull on every encounter
Lens	0	+0.7	+0.35	No	Tilts Curious
Disposition	+0.2	−0.1	+0.05	No	Mildly mixed, neither pole
Tether	+0.2	−0.1	+0.05	No	Roughly balanced

Reading: mildly Curious, conflicted Engagement, neutral on the rest. Their runs will be characterized by argument-events on engagement (push vs. retreat) and a bias toward unusual finds. Always weird, sometimes glorious, sometimes a mess. Player notices: "Brom and Dora always find strange stuff."

Example: Miles + Reynold (both Drunk + Gatherer + Brave) — heavily Wandering, neutral Engagement (both Brave + both wandering = high Tether-negative + high Engagement-positive), mildly Curious. Reading: Bold + Wandering + Curious. They engage everything, follow every tangent, find weird things — but they also come back drunk with immaculate pelts because both are Gatherers with high quality bias on hide. Different flavor entirely from Brom+Dora.

Event weighting

Each authored event has axis affinities — required (hard gate), preferred (soft weight), and conflict-affinity (events that only fire when an axis is conflicted).

def event_weight(event, party):
    weight = 1.0
    for axis in AXES:
        # Hard gates
        if event.required[axis] is not None:
            if sign(party.vector[axis]) != sign(event.required[axis]):
                return 0
            if abs(party.vector[axis]) < event.required_magnitude[axis]:
                return 0

        # Soft preferences
        if event.preferred[axis] is not None:
            if sign(party.vector[axis]) == sign(event.preferred[axis]):
                weight *= 1 + abs(party.vector[axis]) * AFFINITY_STRENGTH

        # Conflict bonus
        if event.prefers_conflicted[axis] and party.conflicted[axis]:
            weight *= CONFLICTED_BONUS

    return weight

Same shape applies to material drop tables. Drops are tagged with axis affinities; the sampler weights drops by party shape. A high-Curious + Wandering party in Burned Hills doesn't get the same haul as a high-Concrete + Disciplined party in the same biome. Same zone, different game.

Signal-to-noise

For folk-knowledge to register, the latent type has to visibly skew outcomes. Working targets:

• Tilted axes (|value| > 0.5) should produce >75/25 bias in event sampling on that axis's affinities
• Conflicted axes should fire conflict-specific events at >30% rate when both poles are represented
• Signature finds (rare items, named events, library-worthy moments) should be latent-gated so they happen to characters who have the right chemistry, not randomly

Players should notice a party's chemistry within 3–5 runs of the same pairing. If the curve is longer than that, the system isn't doing its job.

AI authoring loop

This is what makes the matrix economically viable. Authoring is per-axis-shape, not per-character-pair.

prompt: "Generate 30 expedition events for the Burned Hills biome,
targeting a party reading [high Bold, high Curious, neutral Disposition,
high Wandering, conflicted on nothing]. Tone: darker WoW × Shrek.
~70% flavor pings, ~25% light decisions, ~5% substantive moments.
Tag each with required/preferred axis affinities."

→ AI produces a tagged event pool.
→ Runtime sampler weights toward party-matching events.

A few hundred prompts cover 16 types × ~5 biomes × ~3 leg-stages at sufficient density. The pool tags itself. Adding events post-launch is the same pipeline, indefinitely. The system gets richer over time without redesigning anything.

Signature events — the rare, character-naming ones — gate to specific latent shapes. "Found the 90lb onyx" only fires for high-Curious + Wandering parties, so when it happens to your Brom and Dora, it feels like their story. Because it is.

Material properties as expression of party choice

This is the closing loop — the part that makes the matrix more than a flavor system. Material properties are exposed through the party profile.

The pipeline

Party latent vector
  ↓
Material drop weights (tagged by axis affinity)
  ↓
Material properties surface based on what comes back
  ↓
Recipes reflect the materials available
  ↓
Crafted items express the materials' character
  ↓
Items carry the tone of the run that produced them

A whimsical party (high Curious + high Wandering) brings back whimsical materials — odd provenances, unusual properties, cursed-by-storage edge cases. Those materials demand recipes that handle their character. The recipes the player actually engages with are the recipes that work with what they have to work with. The crafted items inherit the absurdity.

A pragmatic party (high Concrete + high Disciplined) brings back clean ore, predictable hides, standard botanicals. Their recipes are the clean ones. Their items are the reliable ones.

Tone emerges from play

The game is agnostic to the "best" path. There is no canonically optimal flavor. Players gravitate naturally to combinations that resonate with them — some lean whimsy, some lean grim, some lean efficient. The game's tonal character on a given save is produced by the player's pairing choices.

This is structurally significant:

• No tone authored by the designer. The whimsy / seriousness mix on a given save is a player-driven outcome. Two players have demonstrably different games.
• Recipes don't drive expedition choices; expedition choices drive which recipes matter. This inverts the conventional crafting-game flow. Materials → recipes → items, not the other way around.
• Absurd parties get absurd items, which fuel more absurdity. A whimsy spiral is positively reinforced by play. So is a serious spiral. The player's gravitational well deepens with each run.
• No "wrong" way to play. Min-maxing optimal Concrete + Disciplined builds produces a coherent serious-craft game. Min-maxing chaotic Curious + Wandering produces a coherent whimsy game. Both are legitimate, both are deep.

This is the design pillar this whole session was building toward. The expedition system + party matrix + material properties together form a player-expression engine — the player's flavor of the game emerges from their roster choices, not from a tone dial the designer set.

Property exposure mechanics

Materials have multiple layers of identity (14-materials.md covers type + quality):

• Provenance — where it came from (Burned Hills moonsilver smelts hotter than Mire moonsilver). Set on drop.
• State — fresh / aged / cured / cursed-by-storage. Time-evolves.
• Properties — discovered through use. First few crafts surface property hints. Library populates.
• Axis tags — invisible to player; biased by the producing party's latent vector. Drives what can be discovered, what can be crafted.

A high-Curious party's haul might include moonsilver tagged with whimsy-affinity. That moonsilver, when used in a recipe, biases the output toward absurd variants — propeller-hat results, rhinestone-decorations, lumbass-bread effects. The player doesn't see the tags. They just notice: "the things I make with this kind of party always come out weird."

Open threads

• Axis selection — Engagement / Lens / Disposition / Tether is a working set. Want to prototype with placeholder axes and verify event ideas slot in naturally before locking. The four axes are load-bearing; wrong axes produce bland or contradictory output.
• Combination math — current sketch is per-axis mean + conflicted flag. May need to weight by trait strength (Brave is louder on Engagement than Cautious; Drunk is loud on Tether but mild on Lens). Sim-tuneable.
• Conflicted-axis event density — too many conflict events makes mixed parties feel like a mess. Too few makes the conflict-as-spice mechanic vanish. Target ~30% fire rate when conditions met, tune in sim.
• Folk-knowledge surfacing aids — beyond just outcomes, do we audio-tell, visually-tell, narratively-tell what kind of run this is? Subtle cues (different music sting, different report tone, different narrator voice) help players read the chemistry without spelling it out.
• Stable-pairing pull — folk knowledge requires repeated pairings. Current roster mechanics (mix-and-match, hire pool churn) may pull against this. Bond-via-shared-runs is the natural lever; may need other nudges (paired training, paired equipment, shared dwellings) to keep ~3–5 favorite duos in heavy rotation.
• Material property authoring — how many distinct properties per material category? How are they procedurally generated vs. hand-authored? AI batching here is similar to event authoring; same pipeline likely applies.
• Surfacing without exposing — Library entries that say "Brom and Dora have an unusual rapport in the field" are surfacing the consequence without exposing the math. How explicit does this go? Too explicit = "MBTI score." Too implicit = invisible. Target the middle: Library notes patterns observed, never underlying axes.

What this commits to

Nothing yet — this is brainstorm notes. But the design is now coherent enough that the next session can move on whether the player-expression engine is the right pillar to anchor on, or whether it's overreach for a 6-month solo build. The sim (17-foldins § Data pipeline) will need to model latent-axis dynamics to estimate authoring cost, content variety per save, and whether the folk-knowledge curve actually lands in 3–5 runs.