Deck Primer
The Deck Primer page (/deck-primer) builds a prompt you paste into ChatGPT or Claude to get back a deck primer — a structured, pilot-facing guide for playing a Commander deck. A primer can cover the commander's identity and role, win conditions and card choices, verified combo lines, gameplay sequencing and mulligan rules, matchup strategy, budget cuts and upgrade paths, and common-mistake reminders.
DeckFlow does not write the primer itself. It assembles a prompt grounded in your real decklist, live combo data, and metagame context, so the AI answers from facts instead of guessing. You pick which sections you want, copy the prompt, and paste it into your AI.
The workflow is three steps.
Step 1 — Import the deck
Choose an Input method:
- Paste text — paste exported deck text (Moxfield bulk-editor output, Archidekt export, MTG Arena export, or plain text).
- Use public deck URL — paste a public Moxfield or Archidekt deck URL (for example
https://moxfield.com/decks/…orhttps://archidekt.com/decks/…).
The deck is parsed and resolved. It must contain a commander and at least one mainboard card, or an error is shown. The chosen input method round-trips with the form, so it survives refreshes and step navigation.
Step 2 — Choose bracket, AI platform, and sections
Configure the primer:
| Setting | Purpose |
|---|---|
| AI platform | ChatGPT or Claude. This selects which prompt variant Step 3 shows — the wording is tuned per platform. |
| Target Commander Bracket | Exhibition, Core, Upgraded, Optimized (default), or cEDH. The bracket controls which sections are available and which matchup/meta context is pulled in. |
| Primer style | Standard (clean, paste-anywhere markdown) or Moxfield-style rich (adds a clickable table of contents, callout boxes, collapsible combo lines, matchup tables, and ASCII/markdown visuals for pasting into a Moxfield description). At the cEDH bracket a third option, Full cEDH primer, appears: it uses the rich formatting, forces full cEDH section coverage, and asks for extra competitive depth (fast-mana lines, operating under stax, free-interaction counts, win-by-turn windows, and named-archetype matchups). |
| Primer sections | The parts of the primer you want the AI to write. |
Sections are grouped into five collapsible groups — Identity, Combos, Gameplay, Matchups, and Maintenance — with checkboxes for each section and a running "selected" count per group. Each section has a short "What this adds" note describing what good AI output for that part looks like.
The available sections depend on the bracket. Some are cEDH only (for example a cEDH-metagame matchup section), and some are Brackets 1–4 only (for example battlecruiser-politics guidance). The list updates as you change the bracket. If you leave the section choices alone, a sensible preset for the selected bracket is used.
Click Generate Primer to build the prompt. When building, DeckFlow:
- Loads and parses the deck and resolves the commander.
- Queries the Commander Spellbook API for verified combos and near-combos in the list.
- For cEDH, pulls current archetype names from EDH Top 16 for the matchup targets.
- Counts functional roles (ramp, draw, tutors, interaction) from category knowledge to ground the deck summary.
Step 3 — Generate and copy the prompt
Step 3 shows three things:
- Suggested chat title — for example
Deck Name | Deck Primer. Rename your AI conversation to this before pasting, so the primer is easy to find later. A copy button is provided. - Deck summary — mainboard/maybeboard/sideboard counts, commander, bracket and format, and the ramp/draw/tutor/interaction breakdown when it could be grounded.
- Primer prompt — the prompt to paste into your AI, with a copy button and an approximate size (for example
~2.5 KB). If the prompt is large enough to risk exceeding the platform's paste limit, a caution appears suggesting you trim sections or paste in parts.
Copy the prompt, paste it into ChatGPT or Claude, and the AI returns the finished primer inside a single fenced markdown block, with sections in the order you selected. With Moxfield-style rich or Full cEDH primer selected, the prompt also asks for a table of contents, callout boxes, collapsible combo lines, tables, and ASCII/markdown visuals.
Saving and resuming a session
Use Download session (.zip) to save the current setup — deck source, bracket, AI platform, and selected sections — along with the generated prompt variants and the normalized decklist. Use Upload & Resume later to restore that setup from the .zip. The saved primer is restored verbatim — DeckFlow does not auto-rebuild it or re-fetch combo/meta data on resume. To refresh a primer against newer data, regenerate it explicitly with Generate Primer (or the Regenerate primer button described below).
Staleness banner (optional)
When the site operator has enabled the tool.primer.stale-flag feature flag, Step 3 warns you when a restored primer no longer matches the deck currently in Step 1. If you Upload & Resume a primer .zip while Step 1 holds a different deck, the old primer still renders verbatim, but a caution banner appears — "Deck changed since this primer was generated — N cards differ. Regenerate to refresh the primer." — with a Regenerate primer button.
Staleness is a card-name-and-quantity comparison: reordering cards or swapping printings does not flag stale, while adding or removing a card, or changing a quantity, does. Nothing rebuilds on its own — regeneration is always the explicit button press. With the flag off, Step 3 and the downloaded zips are unchanged.