SBT Storage Contract (Onchain vs Offchain)

Onchain source (Move contract)

• Struct: contracts/sources/nft_dnd.move:90 (HeroSBT)
• Mint entrypoint: contracts/sources/nft_dnd.move:460 (mint_hero_sbt)
• Progress entrypoint: contracts/sources/nft_dnd.move:594 (update_hero_progress)

Onchain fields (HeroSBT)

Stored directly onchain:

• Identity/profile: owner, hero_name, hero_class, ancestry, alignment, deity, title, background
• Core stats: stat_str, stat_dex, stat_con, stat_int, stat_wis, stat_cha
• Core derived values: hp_max, armor_class, starting_gold_gp, gear_slots
• Compact text payloads: languages_csv, talents_csv, known_spells_csv
• Metadata cids/rules: origin_lore_cid, portrait_cid, hero_sheet_cid, ruleset_id
• Progress and timestamps: created_at_ms, level, xp, lore_score

Offchain snapshot (DB/state)

Stored in characters.state.onchain.heroSbtSnapshot and related state:

• snapshotVersion, ruleset
• Expanded starter inventory array, slot usage metrics (gearSlotsUsed, gearSlotsFree)
• Carry rule strings and starter inventory metadata
• Optional creation audit metadata (state.creation.*) including roll source and limits

Mint validation contract in app

Before sending mint_hero_sbt, client validates:

• Stats within 3..18
• Class/ancestry validity and profile consistency
• Stats satisfy strict profile limits
• gearSlots matches strict formula
• HP/AC/gold positive and required identity fields present

Code: client/src/lib/OneChain.ts:269

Post-adventure update split

Onchain mutable progression (now)

• level
• xp
• lore_score

Via: update_hero_progress (client/src/lib/OneChain.ts:426)

Offchain mutable progression (now)

• Inventory/loadout deltas
• Starter inventory replacements/consumption
• Slot usage (gearSlotsUsed, gearSlotsFree)

Via: applyAdventureProgressToHeroSnapshot (client/src/lib/shadowdarkSbt.ts:309)

Snapshot migration notes

• Current canonical snapshot: hero-sbt-v2
• Legacy snapshots should be read with defaults for newly added inventory/slot metadata
• Migration policy: treat onchain fields as source of truth for immutable-ish core; enrich offchain document on read/write