Codex Localis — Your Campaign's Co-GM

The GM's Grimoire.
Powered by Your Books.

A local-first AI assistant that reads your sourcebooks and thinks in your system.

CoLoci (Co-low-key) indexes your RPG PDFs — stat blocks, character creation, item tables — and gives you setting-informed, system-aware answers on demand. It handles the scaffolding. You bring the world to life.

First 50 generations free  ·  No account required  ·  Runs on Ollama — your machine, your models, your data
🔒 100% Local
🧠 Powered by Ollama
📴 No Cloud. Ever.
📚 Your PDFs. Your Models.
CoLoci — Codex Localis  v0.5.0
CoLoci main interface

What CoLoci Is — And Isn't

A Co-GM, Not a Replacement

Being a great GM isn't about knowing every stat or building every NPC from scratch — it's about being present at the table and making the world breathe. CoLoci takes the grind off your plate so you can pour your energy where it actually matters.

⚒️
CoLoci Handles the Scaffolding
Give it a prompt — "I need a mid-level Tremere NPC with a grudge and a secret" — and CoLoci pulls from your indexed sourcebooks to produce a complete, rules-grounded draft. Stat blocks, motivations, hooks, lore-appropriate abilities. Done in seconds. The rest is yours to make real.
🎭
You Bring It to Life
The voice, the timing, the read on your table — that's the part no tool can replace, and it's where great GMs shine. CoLoci reduces the friction of building so you arrive at that creative moment faster and with more energy left to spend on it.

How It Works

From Your Shelf to Your Table

Step I 📚
Index Your PDFs

Point CoLoci at your sourcebooks. It reads character creation chapters, stat blocks, item tables, and bestiary entries — understanding your system's structure, not just its text.

Step II 🧠
Ask Anything

Type your prompt the way you'd ask a fellow GM. "Build me a Shadowrun fixer with ties to the Yakuza." CoLoci searches your indexed library and generates a system-aware answer using the model you choose.

Step III ✒️
Refine and Run

Tweak, export, or drop directly into your notes. Everything stays on your machine — no cloud, no subscription, no sending your campaign to someone else's server.

Truly Local. Genuinely Private.

Your Campaign Never Leaves Your Machine

CoLoci runs on Ollama — an open-source local model runner. You choose the model. You own the hardware. Nothing is ever sent to a remote server.

  • Use any model available in Ollama — llama, mistral, gemma, qwen, and more
  • Run multiple models and switch between them per session or per task
  • Your PDFs, notes, and generated content stay on your disk, always
  • No API keys. No usage tracking. No telemetry.
  • Air-gapped campaigns are fully supported — no internet required after setup
0
Bytes sent to
any server
Models to
choose from
8 GB
RAM to get
started
16 GB
RAM for the
best experience

Deep PDF Understanding

It Knows Where Everything Lives

Most tools treat a PDF like a wall of text. CoLoci understands the structure of RPG sourcebooks — where character generation lives, how stat blocks are formatted, what the item tables mean for your system.

  • Finds and parses character creation rules to generate rules-grounded builds
  • Reads item and equipment tables — gear, costs, and encumbrance drawn from your indexed books
  • Understands NPC and monster stat block formats across supported systems
  • Pulls lore and flavour text to give generated content the right voice
  • Handles multi-book libraries — core rules plus supplements, all indexed together
Library & PDF Index
CoLoci library and PDF indexing

Generation in Seconds

NPCs That Actually Fit Your World

No more generic stat blocks. CoLoci generates NPCs, encounters, and items grounded in your indexed sourcebooks — abilities and power levels drawn from your books, with the right flavour for your setting.

  • Full NPCs with stats, motivations, hooks, and secrets
  • Encounters designed around your party's level and system's math
  • Rules lookups that reference the relevant pages in your actual books
  • Session recaps and plot hook generation from your campaign notes
NPC Generation Output
CoLoci NPC generation output

System Knowledge

Built for Your Game

CoLoci has specialist knowledge of these systems — not just their text, but their structure, their math, and the way their sourcebooks are organised.

World of Darkness
VtM · WtA · MtA & more
D&D 5e
Core & supplements
Pathfinder
1e & 2e
Shadowrun
5e & 6e

More systems coming soon — your sourcebooks, your call.

Who It's For

Built for the Way You Run Games

Whether you're cracking open a new mystery tonight or threading a three-year epic, CoLoci meets you where you are.

🔍
Monster of the Week & One-Shots

You've got a mystery to run Friday and no time to build a custom move, an antagonist, and three supporting NPCs from scratch. CoLoci generates a complete, playable mystery frame — locations, the monster's countdown, Bystander motivations — in minutes. You add the details that make it yours, and arrive at the table ready to be fully present.

📜
Long-Running Campaigns

Three years in, your world has history. CoLoci indexes your session notes alongside your sourcebooks so generated content fits the continuity you've already built. Need a new faction NPC who respects the politics you've established? It reads the room — because you taught it your world.

Monster of the Week — Mystery Generation
CoLoci Monster of the Week mystery generation output

Pricing

Try It Free. Own It Forever.

No subscriptions. No cloud. Download the full app, use it for your first 50 generations on us — then buy a lifetime license when you're ready.

Try It Free
$0
No account · No card · No expiry
  • Full app — every feature unlocked
  • 50 generations to put it through its paces
  • Index your own PDFs from day one
  • Use any Ollama model you have downloaded
  • Runs 100% on your machine
Download for Mac Coming Soon
Download for Windows Coming Soon

Licensing powered by LemonSqueezy  ·  Secure checkout  ·  Instant delivery

Questions

Frequently Asked

No — and it's not trying to. CoLoci gets you to an 80–90% answer fast: a valid NPC, a workable encounter, a rules citation you'd have spent 20 minutes finding. That last stretch — the voice, the timing, the read on your players — is irreplaceable, and it's yours. CoLoci just clears the grind so you arrive at that moment with more energy to spend on it.
Never. CoLoci runs entirely locally via Ollama. Your PDFs, your campaign notes, your generated content — none of it touches a remote server. There is no CoLoci cloud. The LLM runs on your hardware. Your campaign stays yours, full stop.
Any model you can pull in Ollama — llama3, mistral, gemma, qwen, phi, and more. You can have multiple models downloaded and switch between them at any time. Use a fast, lighter model for quick lookups and a larger, more capable one for complex NPC generation — it's entirely up to you.
Yes. Each tab in CoLoci has its own instruction set you can tune — set the tone, the setting details, the level of detail you want in responses. One tab might be configured for quick NPC names in your city-state; another for deep lore generation for your antagonist faction. The output feels like it came from someone who read your notes, because you wrote the brief.
CoLoci currently runs on macOS and Windows. 8 GB RAM is enough to get started with lighter models. 16 GB RAM is where CoLoci really opens up — larger models, faster responses, better output. The more RAM you can give Ollama, the better your experience in both generation speed and quality. Apple Silicon Macs (M1 and later) deliver particularly strong performance thanks to unified memory.
CoLoci has specialist structural knowledge for World of Darkness, D&D 5e, Pathfinder, and Shadowrun — meaning it understands how those books are laid out, not just what they say. For other systems, it can still index and search your PDFs and generate content, but without system-specific parsing. More systems are actively in development.
Yes. One payment, the app is yours. Future system updates and new specialist knowledge are included for license holders. No subscription, no renewal, no gotcha.

Your Next Session Is Waiting.

Download CoLoci, index your books, and see what prep feels like when the scaffolding is handled — so you can spend your energy on the part only you can do.

50 free generations  ·  No account  ·  Runs on Ollama — your machine, your models