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From d20-system
This skill should be used when the GM needs to help players create characters, roll for stats, assign ability scores, handle leveling up, increase hit points, choose classes, pick proficiencies, or manage player character creation, advancement, or character sheet management. Provides templates and rules for SRD 5.2 character creation and leveling.
npx claudepluginhub rjroy/adventure-engine-corvran --plugin d20-systemHow this skill is triggered — by the user, by Claude, or both
Slash command
/d20-system:d20-playersThe summary Claude sees in its skill listing — used to decide when to auto-load this skill
Guide players through creating and advancing d20 system characters following SRD 5.2 rules.
Manages D&D 5e campaigns with MCP tools for creating modules, NPCs, characters, encounters; homebrew monsters/items/spells; catalog searches; map/token placement; document handling.
Roll dice and interpret results for tabletop RPGs using RANDSUM notation. Supports various modifiers and game systems like D&D 5E, Blades in the Dark, PbtA.
Share bugs, ideas, or general feedback.
Guide players through creating and advancing d20 system characters following SRD 5.2 rules.
Character files follow the corvran directory structure with D20-specific content:
players/
{character-slug}/
sheet.md # Use sheet-template.md format (stats, abilities, equipment, current HP, conditions)
story.md # Use story-template.md format (objectives, story arcs, recent events)
The sheet.md contains character data including current game state (HP, conditions, spell slots). The story.md tracks narrative elements like objectives and story arcs.
Follow these five steps to create a new character:
Offer three methods to generate the six ability scores.
Use these six scores, assigning each to one ability: 15, 14, 13, 12, 10, 8
For each of the six abilities, roll 4d6 and sum the highest three dice:
Use the mcp__corvran__roll_dice tool:
{ "groups": [{ "n": 4, "d": 6 }] }
Discard the lowest roll from the result and sum the remaining three. Repeat six times.
Start with 27 points. Each ability starts at 8 (free). Costs to increase:
| Score | Total Cost | Score | Total Cost |
|---|---|---|---|
| 8 | 0 | 12 | 4 |
| 9 | 1 | 13 | 5 |
| 10 | 2 | 14 | 7 |
| 11 | 3 | 15 | 9 |
After assigning ability scores, calculate these values:
Modifier = (Score - 10) / 2, rounded down
| Score | Modifier | Score | Modifier |
|---|---|---|---|
| 8-9 | -1 | 14-15 | +2 |
| 10-11 | +0 | 16-17 | +3 |
| 12-13 | +1 | 18-19 | +4 |
| Level | Bonus | Level | Bonus |
|---|---|---|---|
| 1-4 | +2 | 13-16 | +5 |
| 5-8 | +3 | 17-20 | +6 |
| 9-12 | +4 |
| Class | HP at Level 1 |
|---|---|
| Barbarian | 12 + CON modifier |
| Fighter, Paladin, Ranger | 10 + CON modifier |
| Bard, Cleric, Druid, Monk, Rogue, Warlock | 8 + CON modifier |
| Sorcerer, Wizard | 6 + CON modifier |
Without armor: 10 + DEX modifier
With armor, use the armor's AC formula from the equipment tables.
Initiative = DEX modifier
Each class grants proficiency in two saving throws. For proficient saves:
Save Bonus = Ability Modifier + Proficiency Bonus
For proficient skills:
Skill Bonus = Ability Modifier + Proficiency Bonus
Passive Perception = 10 + Wisdom (Perception) modifier
Write character data to players/{character-slug}/sheet.md using the D20 template:
references/sheet-template.md
For a completed example, see:
references/sheet-example.md
The sheet.md file must include:
When a character gains enough XP to level up:
| Level | XP Required | Level | XP Required |
|---|---|---|---|
| 2 | 300 | 11 | 85,000 |
| 3 | 900 | 12 | 100,000 |
| 4 | 2,700 | 13 | 120,000 |
| 5 | 6,500 | 14 | 140,000 |
| 6 | 14,000 | 15 | 165,000 |
| 7 | 23,000 | 16 | 195,000 |
| 8 | 34,000 | 17 | 225,000 |
| 9 | 48,000 | 18 | 265,000 |
| 10 | 64,000 | 19 | 305,000 |
| 20 | 355,000 |
Roll HP:
Use the mcp__corvran__roll_dice tool:
{ "groups": [{ "n": 1, "d": 10 }] }
Fixed HP values per level:
| Class | HP per Level |
|---|---|
| Barbarian | 7 + CON modifier |
| Fighter, Paladin, Ranger | 6 + CON modifier |
| Bard, Cleric, Druid, Monk, Rogue, Warlock | 5 + CON modifier |
| Sorcerer, Wizard | 4 + CON modifier |
To take a level in a new class:
Use the mcp__corvran__roll_dice tool for all randomization:
Ability Score (4d6 drop lowest):
Use the mcp__corvran__roll_dice tool:
{ "groups": [{ "n": 4, "d": 6 }] }
Starting Gold (if not using equipment packs):
Use the mcp__corvran__roll_dice tool:
{ "groups": [{ "n": 5, "d": 4 }] }
Trinket Roll:
Use the mcp__corvran__roll_dice tool:
{ "groups": [{ "n": 1, "d": 100 }] }
Detailed rules in this skill's references/ directory:
character-creation.md - Complete SRD 5.2 character creation rulessheet-template.md - Blank character sheet templatestory-template.md - Character story template (objectives, arcs, events)sheet-example.md - Completed Level 3 Fighter example