For cube designers · Free · No signup

Your cube,
diagnosed by bots
that actually draft it.

Paste your cube. We run 500 Monte Carlo drafts with mixed-policy agents, measure deck quality / color balance / archetype survivability, then ask an LLM to propose specific swaps — each one verified by re-simulating with the swap applied.

~3 minutes per run · 1 cube per day per IP · powered by Cardivore
Cardivore devil card logo
500
Monte Carlo drafts
6
Tools in the agent loop
0 – 5
DQI scale
≤ 10
Swaps per report
How it works

Four tools, one verdict.

Every recommendation is earned. The agent reads the metrics before it opens its mouth, and it re-drafts its own proposals before it ships them to you.

01

Survey

Static metrics first — color distribution, curve, rarity mix, removal density. The cheap pass before any drafting.

02

Simulate

500 × 8-seat drafts using greedy, synergy, and adaptive bots. Per-archetype DQI, color contestedness, pick-order timing — all returned as structured metrics.

03

Propose & verify

An LLM ranks candidate swaps via Scryfall search, then re-runs the sim with the swap set applied. Suggestions that don't move the needle get dropped.

What you get

A real diagnosis, not vibes.

Here's an abbreviated preview of the shareable report. Yours will have your cube's name, your weak archetypes, your under-drafted colors, and swap suggestions tied to specific scryfall IDs so you can queue them up in CubeCobra.

Vintage Peasant · Example
360 cards · 500 drafts · 2m 48s
v1 · Sonnet
3.42
/ 5.00 DQI
Healthy — draftable across most seats.
Archetype health
WU Control
78%
UB Mill
54%
BR Sacrifice
62%
RG Stompy
71%
GW Tokens
34%
Top swaps (sample)
SWAP · HIGH IMPACT
Sedraxis Specter → Seasoned Pyromancer
GW Tokens can't beat your removal density. A body generator with card selection shifts the lane without spiking power.
REMOVE · MEDIUM
Mizzium Mortars
30% overdrafted red. Removing one "I win the board" sorcery widens UR's lane.
ADD · MEDIUM
Conclave Mentor
Plugs the GW Tokens playability gap that the baseline sim flagged at 0.34.
Under the hood

Transparent. Reproducible. Nerdy.

Cube folks don't trust black boxes. Every run carries its configuration. If you're skeptical, the sim is the same one the Cardivore app ships — we just point the agent at it.

Simulator
Monte Carlo draft · 8 seats × 3 packs × 15 cards TypeScript port of the Dart sim
Policy mix
70% adaptive · 15% greedy · 15% synergy
Agent
Claude Sonnet via @anthropic-ai/claude-agent-sdk 6 tools, 4-turn cap
Verification
Proposed swaps re-simulated · weak suggestions dropped
Hard caps
$1.50 per run · 3 turns · 1,200 sim draws
Your data
Cube list in, report out. Nothing retained; report page is public and shareable.
Run the Doctor

Diagnose your cube.

~3 minutes. You'll get a shareable report URL when it's done. One free run per IP per 24 hours. Install the app for unlimited runs on your own cubes.

or paste a list
By clicking Run, your cube list will be sent to Cardivore and diagnosed. Report page is public.
Cardivore app icon

Run the Doctor unlimited times, on every cube you own.

Cardivore is a full MTG companion — collection tracking, deck analysis, cube building, card scanning. The Cube Doctor is one of many AI tools inside.

Nerdy questions

FAQ for skeptics.

Why should I trust a bot to draft my cube?

You shouldn't, in isolation. The bots are three distinct policies that each draft badly in predictable, human-ish ways. Across 500 drafts that noise averages out and you can see which archetypes survive, which colors over-draft, and which cards get table-wheeled to death. That's the signal. The LLM reads the signal; it doesn't invent it.

What's DQI actually measuring?

Deck Quality Index (0–5). A weighted composite of threat density (creatures 14–17), answer density (4–6 removal), curve efficiency (avg CMC 2.5–3.2 with 8+ early plays), and consistency (color count + fixing). Sanity caps prevent a 2-creature deck from scoring 5.

Will it suggest cards I already own?

The agent searches cards within your cube's rough power band. It flags out-swap candidates from your cube and in-swap candidates from Scryfall, filtered to format legality. If the suggestions feel off-pitch, tighten your cube's archetype definitions in CubeCobra before running again.

Is this free forever, or is there a catch?

One free run per day per IP while the budget holds (we cap marketing spend at $50/day). Install the Cardivore app to run the Doctor on any cube you've loaded, unlimited.

What's the sim built on?

A TypeScript port of Cardivore's on-device Dart draft simulator. Open source plans pending. Uses a custom LCG RNG so runs are reproducible given the same seed.

Ready when you are.

Paste a CubeCobra URL and go. 3 minutes later you'll have a shareable diagnosis.

Diagnose my cube →