Lexis-AI

Game Systems

Lexis-AI keeps your world (events, ripples, links, hooks, canon) the same in every game. The rules help comes from a system pack: a small set of files that explains one game’s mechanics. You choose the packs when you install (Installation), and each world uses one of them (the system: field in world.md).

Supported systems

| Pack (menu name) | --system id | Based on (the open source it restates) | The roll | Scene tag | Meta-currency | License | |—|—|—|—|—|—|—| | 5E SRD (fifth edition compatible) | srd5 | System Reference Document 5.2.1 by Wizards of the Coast: the free 2024 fifth-edition core rules | d20 + modifier vs DC; Advantage/Disadvantage | scene feature | Heroic Inspiration | CC-BY-4.0 (SRD 5.2.1) | | ORC 2E Core (three-action d20, remaster rules) | orc-d20 | Pathfinder Player Core and GM Core (Paizo, remaster): their ORC-licensed rules | d20 + modifier vs DC, four degrees of success | circumstance | Hero Points | ORC License | | Fate Accelerated | fate-accelerated | Fate Accelerated Edition (Evil Hat) | 4dF + approach vs the ladder | aspect | fate points | CC-BY 3.0 | | Fate Core | fate-core | Fate Core System (Evil Hat) | 4dF + skill vs the ladder | aspect | fate points | CC-BY 3.0 | | d100 Percentile Core (ORC) | d100 | Basic Roleplaying: Universal Game Engine (Chaosium): the percentile engine behind classic investigative horror | d100 ≤ skill %, five success levels | situational modifier | power points as fate points (optional) | ORC License (Chaosium’s Basic Roleplaying engine) | | Forged in the Dark Core | fitd | Blades in the Dark SRD (One Seven Design) and Forged in the Dark games | d6 pool, highest die; position and effect | factor or clock | stress | CC-BY 3.0 (Blades in the Dark SRD) | | Doom d20 Core (OSR, four abilities, Omens) | doom-d20 | MÖRK BORG (compatible, under its Third Party License) | d20 + ability vs DR | DR shift or hazard | Omens | MÖRK BORG Third Party License | | Superhero d20 Effects Core (OGL) | hero-d20 | the effects-based superhero d20 SRD, third edition (OGL)¹ | d20 + rank vs DC, degrees of success | circumstance or condition | Victory Points | OGL 1.0a |

Why the generic names? Most game names are trademarks that the open licenses do not cover. The packs are named after their mechanics, and their pack.md files carry the exact license and attribution text. The Based on column names each source the way its license attribution does, so you can tell which game a pack is for. All trademarks belong to their owners; no pack is affiliated with or endorsed by them.

¹ The source’s product name is Product Identity under the OGL, which forbids using it to claim compatibility, so it is not printed here. The pack follows the third-edition superhero d20 rules published as Open Game Content (ranks, effects, degrees of success, Toughness checks).

What a pack contains, and what it never contains

Contains: how rolls work, difficulty scales, character math (modifiers, hit points, derived values), conditions and harm, how to set up an obstacle, the setup questions for /world-init, and the system sections of character and place files.

Never contains: any published setting (worlds, cities, gods, factions, famous characters, creatures), adventures or story, spell/power/item/monster lists, art, or rule text from games that are not open-licensed. Rules are written as short summaries in our own words. When something depends on your rulebook (a spell, a power, a monster), Lexis-AI names it and tells you to check your book.

The same rule applies to your world: Lexis-AI never brings published setting content into it on its own.

How each system answers

The same request in different systems: “Gabriel climbs the crypt wall in the rain.”

5E SRD

🎲 Ability check
- Check: Strength (Athletics) — hauling himself up · Dexterity (Acrobatics) — quick and light
- Suggested DC: 15 (Medium) — wet stone, but plenty of cracks
- Advantage/Disadvantage: Disadvantage for the rain unless he uses a rope

ORC 2E Core

🎲 Athletics: Climb
- Check: Athletics — the only real choice for climbing
- Suggested DC: 18 (level 3, hard) — slick stone
- Crit success: climbs fast and quiet · Crit failure: falls and takes damage
- Circumstance: −2 circumstance penalty for the rain

Fate Accelerated

🎲 Overcome
- Approach: Careful — testing each handhold · Quick — before the guards turn
- Suggested difficulty: Fair–Good (+2/+3) — "Rain-Slick Stones" works against him

Fate Core

🎲 Overcome
- Skill: Athletics — climbing · Physique — brute force on the drainpipe
- Suggested difficulty: Good (+3) — the wall is high and wet

d100 Percentile Core

🎲 Skill roll: Climb
- Skill: Climb — … · Agility roll (DEX × 5) if he has no Climb skill
- Difficulty: Average — there are handholds
- Modifiers: −20% rain-slick stone
- Special/critical: no noise at all · Fumble: falls from halfway up

Forged in the Dark Core

🎲 Prowl
- Action: Prowl — up the wall in the dark · Finesse — using the drainpipe
- Position: Risky — the patrol passes every few minutes · Effect: Standard
- 4-5: he makes it, but the patrol clock ticks · 1-3: he slips, harm level 1

Doom d20 Core

🎲 Agility test
- Ability: Agility — light and careful · Strength — pulling himself up
- Suggested DR: 14 (difficult) — rain
- Fumble: falls, d6 damage

Superhero d20 Effects Core

🎲 Athletics check
- Trait: Athletics — climbing · Acrobatics — wall-running
- Suggested DC: 15 (tough) — wet stone; routine for a wall-crawler

Per-system notes

5E SRD (srd5)

• d20 tests: ability checks, saving throws, attack rolls; DC 5-30; Advantage/Disadvantage.
• Scene tags are scene features: light and obscurement, cover, Difficult Terrain, hazards, the 15 conditions.
• Obstacles include traps scaled by level, fear and mental stress, social checks with attitudes.
• Characters: ability scores and modifiers, Proficiency Bonus, hit points by class Hit Die, AC, spell save DC; NPCs get a one-line stat line.
• Setup asks: starting level, ability score method, advancement, character option limits, optional rules.

ORC 2E Core (orc-d20)

• Checks with four degrees (critical success / success / failure / critical failure), proficiency ranks, simple and level-based DCs.
• Scene tags are circumstances: circumstance bonuses and penalties, cover, concealment, difficult terrain, valued conditions (frightened 2 …).
• Obstacles: hazards (simple and complex), victory points for multi-step challenges, social attitudes.
• Characters: attribute modifiers and boosts, proficiency, hit points, dying and wounded, Hero Points.
• The pack folder is under the ORC License, with the ORC, attribution and Reserved Material notices in its pack.md.

Fate Accelerated (fate-accelerated) and Fate Core (fate-core)

• 4dF + approach (FAE) or + skill (Core) against the ladder; four actions; outcomes fail / tie / success / success with style.
• Scene tags are aspects, each with an invoke and a compel.
• Obstacles: difficulty ranges on the ladder, hazards as characters, challenges and contests (Core).
• Characters: aspects, approaches or the skill pyramid, stunts, stress and consequences.

d100 Percentile Core (d100)

• d100 roll-under; critical (1/20), special (1/5), success, failure, fumble; Easy (×2) and Difficult (½); situational modifiers ±20% / ±50%; the resistance table.
• Optional Sanity with guideline losses (success/failure, e.g. 0/1D3); temporary insanity.
• Characters: characteristics, characteristic rolls (×5), hit points, major wounds, damage modifier, skill points by power level.
• The pack folder is under the ORC License, with the ORC and attribution notices in its pack.md.

Forged in the Dark Core (fitd)

• d6 pools; 6 full success, 4-5 partial, 1-3 bad, two 6s critical; position (controlled / risky / desperate) and effect (limited / standard / great).
• Scene tags are factors (potency, scale, quality) and clocks (4/6/8 segments).
• Consequences, resistance with stress, harm levels, trauma, teamwork, flashbacks.
• Setup asks what the crew does and whether to use crew rules.

Doom d20 Core (doom-d20)

• Four abilities (−3 to +3), tests against DR 6-18 (12 is normal), short lethal fights, armor tiers, Omens, reactions and morale.
• Rules are restated in our own words under the MÖRK BORG Third Party License; some details (the exact Omen uses, the broken table) are left to your book.

Superhero d20 Effects Core (hero-d20)

• d20 + rank vs DC; degrees every 5 points; damage resisted with Toughness (DC 15 + rank) with the dazed / staggered / incapacitated track; extra effort; power level limits.
• The source’s own names for its two point pools are Product Identity, so the pack calls them Victory Points and Character Points.
• The full Open Game License text and its Section 15 are in the pack’s pack.md.

Not supported

• World of Darkness / Chronicles of Darkness: the rules are not open-licensed (only a non-commercial, revocable fan license exists), so there is no pack.
• Any other system can be used with the closest pack plus your differences under ## Homebrew in system.md. Homebrew always overrides the pack.

Want to add a system? See Creating a system pack.