Dungeon and Dragon Spec-driven development (SDD)

What Do SDD and Dungeons & Dragons Have in Common?

When you saw the title, you probably thought, “Wait, what? What do Specification-Driven Development (SDD) and Dungeons & Dragons (DnD) have to do with each other?” I’m here to share a story about how SDD, a concept from software development, can be surprisingly useful in everyday life — and especially when working with AI.

The Power of the Perfect Prompt

When AI started gaining traction, everyone quickly realized that the magic is in the prompt — the exact instructions you give to get the best results. People began sharing their carefully crafted prompts to replicate stunning custom images or text outputs.

What they didn’t realize was that they were already practicing Specification-Driven Development (SDD) — a method of defining clear, reusable instructions that programmers use to build software.

What is SDD? It’s a way to create detailed, structured specifications that guide development, ensuring consistency and clarity.

They created and shared a specification in the form of a prompt — without the formal formatting and structure typical in IT. Because development doesn’t just mean programming; it means creating something.

My Journey as a New DnD Player

As a big fan of DnD but a complete newbie, I wanted to start playing. But reading all the rules and understanding every exception was overwhelming. How do you even start creating your own character?

That’s when I had an idea: I asked AI to help me build one.

The AI knows all the existing rules, asks the right questions, and helps analyze the best options. It was fun, and I enjoyed the process. But as the prompt grew longer with lots of information, it started to hang and crash. I had to start new chats, which meant transferring data every time.

“Wanted: Kaelen Balam — my DnD character brought to life via AI and Specification-Driven Development.”

The Idea: Using SDD to Manage Complexity

Another good idea: Could I use SDD?

I asked the AI to create a prompt in the form of a specification that I could reuse to start new chats and continue my work seamlessly.

I got my first specification for developing my DnD character.

Handling Multiple Options and Decisions

DnD has many options, and I wasn’t sure in some cases which direction to take, which spells to select, or which fighting style to choose.

So I asked the AI to additional sections

Document all options and decisions I had made or was still undecided about.

Tag my preferred option but keep the others as alternatives I could switch to later.

This way, I could keep track of my choices and easily update them as I learned more.

The Result: A Well-Formatted Specification

The AI generated a nicely formatted spec file documenting:

• All details about my character
• All my requirements
• An overview of stats and spells
• A chapter about future growth and plans

This document became my single source of truth — a reusable, clear guide I could refer to anytime.

Why This Matters Beyond DnD

You can use this approach not only for DnD characters but for any task you do with AI where you need to keep a reusable definition or revert to it when chats start hanging or becoming chaotic.

Think of it as creating a living blueprint for your project that you can update and reuse.

See It in Action

Curious how it looks? Here’s a snippet from my character specification:

Hello, I want to continue playing my character for D&D according to the new 2024 rules. My character just advanced to level 2. Here is the complete character specification, which you must strictly follow:

Name: Kaelen Balam
Race: Swiftstride Shifter (from Monsters of the Multiverse)
Background: Outlander (2024 backward compatibility rules)
Starting Feat (Origin Feat): Skilled (Chosen skills and tools: Sleight of Hand, Herbalism Kit, Poisoner's Kit)
Class: Ranger, level 2
Attributes (Stats):

STR: 10 (+0) | DEX: 17 (+3) | CON: 14 (+2)
INT: 10 (+0) | WIS: 15 (+2) | CHA: 8 (-1)
Saving Throws: Strength, Dexterity
AC (Armor Class): 15 (Chain Shirt / Studded Leather Armor)
Skills and Tools:

Acrobatics (racial) -> +5 bonus
Survival (background) -> +4 bonus
Athletics (background) -> +2 bonus
Stealth (Ranger class + EXPERTISE) -> +7 bonus
Perception (Ranger class + EXPERTISE) -> +6 bonus
Sleight of Hand (Skilled feat) -> +5 bonus (for throwing knives and quick juggling)
Herbalism Kit proficiency (Skilled feat) -> for crafting healing potions
Poisoner's Kit proficiency (Skilled feat) -> for making and applying poisons to weapons
Note: The character does not have Thieves' Tools and does not look for traps. Relies on instincts.
Abilities and Spellcasting at level 2 (D&D 2024):

Favored Enemy ability: The spell Hunter's Mark is always prepared and can be cast 2 times per day for free without using a spell slot.
Spellcasting: I have 2 level 1 spell slots per day. Each day I prepare 3 spells from the entire Ranger spell list.
--- ⚔️ FIGHTING STYLE (Fighting Style Feat) - CURRENT OPTIONS ---
I’m not 100% decided yet, so keep these 3 options open in the conversation for me to switch between:

[Main favorite] Option C: Thrown Weapon Fighting (+2 damage on every dagger throw, drawing the weapon is part of the attack).
Option A: Two-Weapon Fighting (+3 DEX modifier added to damage on off-hand melee attack via Nick trait).
Option B: Archery (+2 to hit rolls with ranged weapons/bows).
--- 🔮 SPELL MANAGEMENT (Prepared vs. Backup Spells) ---
As a 2024 Ranger, I have access to ALL level 1 spells below. After each Long Rest, I can swap any prepared spell for any backup ("sleeping") spell from reserve.

[A] CURRENTLY PREPARED TRIO (My primary combat setup):

Absorb Elements (Cast as a REACTION outside my turn, halves elemental damage and adds bonus to next attack. Does NOT use Bonus Action!)
Fog Cloud (Creates a misty cloud for tactical cover and retreat)
Longstrider (Increases speed by 10 feet for 1 hour for me or Nyx, no concentration)
[B] BACKUP ALTERNATIVES (Often considered for quick swap after Long Rest):

Ensnaring Strike (Entangling attack - Bonus Action right after a hit, ideal for Nyx to gain Advantage)
Alarm (Alarm spell to secure camp against ambush)
[C] WIDER SLEEPING LIST (All other level 1 spells I know and can activate after Long Rest as needed):

Hail of Thorns (Area thorn explosion on ranged weapon hit)
Searing Smite (Ignites target, burning at start of their turns)
Speak with Animals (Communicate with forest fauna for info)
Animal Friendship (Charm a wild creature for 24 hours)
Cure Wounds (Emergency touch healing 2d8 + WIS)
Jump (Triple jump distance/height for me or Nyx)
Hunter's Pace / Expeditious Retreat (Quick escape/sprint via Bonus Action)
Detect Magic (Detect magic nearby)
Detect Poison and Disease (Detect poisons/diseases)
Locate Animals or Plants (Locate animals or specific plants/fungi for my kits)
(Note: I ignore Goodberry due to my own potion crafting via Herbalism Kit.)
Equipment:
1x Short Sword (Trait: Vex), 10x Throwing Daggers (Traits: Nick, Thrown), Longbow + 20 arrows, Explorer's Pack, Herbalism Kit, Poisoner's Kit. Thanks to 2024 rules, I can freely draw daggers for throwing and at the end of the action freely draw the sword for defense. I do not buy poison or potion ingredients, I gather them via Survival/Perception.

Future plans:

Level 3: Beast Master subclass (panther named Nyx, Beast of the Land profile). Synergy with knocking enemies prone.
Level 4: Sharpshooter feat (Throwing daggers up to 60 feet without disadvantage, ignore cover, cancels point-blank disadvantage).
--- Your task for this chat ---
Help me run the character, simulate combat, and calculate mechanics according to 2024 rules. Respect that I can swap spells between sections [A], [B], and [C] after Long Rests.

Final Thoughts

Using SDD with AI helped me overcome the complexity of DnD character creation and gave me a reusable, clear framework to build on. If you’re working on any complex project with AI, try creating your own specification — it might just save you time and frustration.

Thanks for reading! If you found this useful, please clap or share your thoughts in the comments. Have you tried using SDD or similar methods with AI? I’d love to hear your experiences.