| name | creating-commander-decks |
| description | This skill should be used when the user asks to "build a Commander deck", "create an EDH deck", "make a deck for [commander name]", "fill out a partial decklist", "add a deck to the collection", or mentions building a new Commander/EDH deck from a commander name. |
| version | 1.0.0 |
Creating Commander Decks
Overview
End-to-end workflow for building a Commander deck from a commander name to finished, validated files. Produces a deck JSON and companion README in decks/.
When to Use
- User names a commander and wants a deck built
- User has a partial card list and wants it completed
- User wants to add a new deck to the
decks/ collection
Workflow
digraph deck_flow {
rankdir=TB;
node [shape=box];
start [label="User provides commander name" shape=doublecircle];
validate [label="1. Validate commander\n(Scryfall API)"];
research [label="2. Research on EDHREC\n(popular cards, themes, combos)"];
identity [label="3. Define deck identity\n(theme, bracket, budget)"];
build [label="4. Build card list\n(fill all categories)"];
bracket_check [label="5. Validate bracket compliance"];
bracket_ok [label="Bracket rules pass?" shape=diamond];
fix [label="Swap offending cards"];
prices [label="6. Fetch prices\n(prices.py / Scryfall)"];
budget_ok [label="Within budget?" shape=diamond];
swap [label="Find cheaper alternatives"];
json [label="7. Write deck JSON"];
readme [label="8. Write deck README"];
verify [label="9. Verify everything"];
done [label="Done" shape=doublecircle];
start -> validate -> research -> identity -> build -> bracket_check;
bracket_check -> bracket_ok;
bracket_ok -> prices [label="yes"];
bracket_ok -> fix [label="no"];
fix -> bracket_check;
prices -> budget_ok;
budget_ok -> json [label="yes or no budget"];
budget_ok -> swap [label="over budget"];
swap -> prices;
json -> readme -> verify -> done;
}
Step 1: Validate Commander
Query Scryfall: GET https://api.scryfall.com/cards/named?exact={name}
Extract: name, colors, color_identity, mana_cost, type_line, oracle_text. Confirm the card is a legal commander (legendary creature or has "can be your commander").
Step 2: Research on EDHREC
Fetch the commander's EDHREC page for:
- High synergy cards and staples for the color identity
- Common themes/archetypes
- Typical combo lines
- Average deck composition
Use this as a starting point, not a copy-paste. The user's theme and bracket filter what's appropriate.
Step 3: Define Deck Identity
Confirm with the user:
- Theme: one-sentence concept (e.g., "dwarves tap for Treasures to tutor artifacts and dragons")
- Target bracket (1-5): constrains card quality, combos, Game Changers
- Card count: 100 standard, 112 for MPC.com printing
- Budget: optional ceiling; skip if user doesn't mention it
Step 4: Build Card List
Fill categories to hit roughly these counts (for 100-card deck):
| Category | Target Range |
|---|
| Commander | 1 |
| Creature | 25-35 |
| Instant | 5-10 |
| Sorcery | 5-10 |
| Enchantment | 5-10 |
| Artifact | 8-15 |
| Planeswalker | 0-3 |
| Land | 34-38 |
Categories used in JSON: commander, creature, planeswalker, sorcery, instant, enchantment, artifact, land.
Step 5: Validate Bracket Compliance
Cross-reference the card list against bracket rules. For the full bracket rule table and Game Changers list, consult references/bracket-rules.md.
Flag Rule 0 considerations: cards that are technically legal for the bracket but may draw table discussion (e.g., From the Ashes as soft mass LD in bracket 3, Blood Moon changing land types).
Step 6: Fetch Prices
Run the bundled pricing script:
python3 ${CLAUDE_PLUGIN_ROOT}/scripts/prices.py {deck-slug}
Or use Scryfall API directly. Summarize: total cost, top 10 expensive cards, cost by category. If user set a budget, identify cards to swap for cheaper alternatives.
Scryfall rate limit: 50-100ms between requests. Use User-Agent: MTGDeckTracker/1.0. On macOS, use SSL context with /etc/ssl/cert.pem.
Step 7: Write Deck JSON
File: decks/{commander-slug}.json
For the full JSON schema and color identity reference, consult references/deck-format.md.
Group cards by category in the array. Basics use their total quantity (e.g., "quantity": 24 for Mountains).
Step 8: Write Deck README
File: decks/{commander-slug}.md
Structure:
# Commander Name
**Color Identity:** {identity} | **Bracket:** {n} ({name}) | **Cards:** {count}
## Theme
One or two sentences.
## How It Plays
Short paragraph on core game plan.
## Key Cards
5-8 cards with brief notes on why they matter.
## Bracket Notes
Game Changers count, Rule 0 flags.
## Card Breakdown
Table with category counts.
## Decklist
### Commander (1)
1x Commander Name
### Creatures (28)
1x Card Name
1x Card Name
### Instants (10)
1x Card Name
...
### Lands (36)
1x Card Name
14x Mountain
Each category header includes the total card count for that category. Cards listed as {quantity}x {name}. Categories appear in this order: Commander, Creatures, Planeswalkers, Sorceries, Instants, Enchantments, Artifacts, Lands. Empty categories are omitted.
Step 9: Verify
- Sum of all card quantities matches
card_count
- Category counts in README match actual JSON data
- Decklist in README lists every card from the JSON with correct quantities
- Bracket notes accurately reflect Game Changers count
- All card names are real (validated against Scryfall)
- Commander slug in filename matches JSON content
Common Mistakes
- Miscounting lands: basics have high quantity values — don't count them as 1
- Game Changers misidentification: always check the official list; many strong cards (Sol Ring, Exploration, Scapeshift) are NOT Game Changers
- Forgetting Rule 0 flags: cards like Blood Moon or From the Ashes are bracket-legal but worth noting
- Wrong color identity names: it's "Gruul" not "Red/Green" in the JSON field
Additional Resources
Reference Files
references/bracket-rules.md — Full bracket rule table, Game Changers list, and compliance checking guidereferences/deck-format.md — Complete JSON schema, color identity names, and example deck structure
Scripts
${CLAUDE_PLUGIN_ROOT}/scripts/prices.py — Fetch card prices from Scryfall API for a deck or all decks
