build-tcg-deck

name	build-tcg-deck
description	Build a competitive or casual trading card game deck from scratch. Use when the user explicitly asks to create, build, or construct a TCG deck, wants a deck list for Pokemon TCG/MTG/FaB, or needs help with archetype selection and card choices. Covers archetype selection, mana/energy curve analysis, win condition identification, meta-game positioning, and sideboard construction for Pokemon TCG, Magic: The Gathering, Flesh and Blood, and other major TCGs. Do NOT use for: card condition grading (use grade-tcg-card), collection inventory management (use manage-tcg-collection), rules questions, price checking, or explaining how a specific existing deck works without building it.
license	MIT
allowed-tools	Read Grep Glob WebFetch WebSearch
metadata	{"author":"Philipp Thoss","version":"1.1","domain":"tcg","complexity":"intermediate","language":"natural","tags":"tcg, deck-building, pokemon, mtg, fab, strategy, meta, archetype"}

Build TCG Deck

Construct a trading card game deck from archetype selection through final optimization, following a structured process that works across Pokemon TCG, Magic: The Gathering, Flesh and Blood, and other major TCGs.

When to Use

Trigger this skill when the user explicitly requests:

• "Build me a [game] deck" or "Create a deck for [format]"
• "I need a deck list for [archetype/strategy]"
• "Help me construct a competitive deck"
• "What cards should I put in my [archetype] deck?"
• "Optimize my deck list" or "Improve this deck"

When NOT to Use

Do NOT trigger this skill for:

• Card condition assessment or grading (use grade-tcg-card instead)
• Collection inventory tracking or management (use manage-tcg-collection instead)
• Rules questions about specific card interactions
• Price checking or market value inquiries
• Explaining how an existing tier deck works without modifying/building it
• Sideboard advice in isolation without main deck context
• Deck critique without the user asking for construction help

Inputs

• Required: Card game (Pokemon TCG, MTG, FaB, etc.)
• Required: Format (Standard, Expanded, Modern, Legacy, Blitz, etc.)
• Required: Goal (competitive tournament, casual play, budget build)
• Optional: Preferred archetype or strategy (aggro, control, combo, midrange)
• Optional: Budget constraints (maximum spend, cards already owned)
• Optional: Current meta-game snapshot (top decks, expected field)

Procedure

Step 1: Define the Archetype

Choose the deck's strategic identity. Gather missing inputs through direct user questions if not provided.

1. Confirm required inputs by asking the user if not provided:

   • "What TCG are you building for?"
   • "What format (Standard, Expanded, Modern, etc.)?"
   • "Is this for competitive play, casual, or budget?"

2. Identify available archetypes in the current format by researching recent tournament results:

   • Use WebSearch to find "[game] [format] tier list" or "[game] [format] meta [current month/year]"
   • Document the top 5 archetypes with brief descriptions

3. Select an archetype based on:

   • Player preference and playstyle (ask: "Do you prefer aggressive, controlling, or combo strategies?")
   • Meta-game positioning (what beats the top 3 most played decks?)
   • Budget constraints (combo decks often need specific expensive cards)
   • Format legality (check ban lists and rotation status via WebSearch if needed)

4. Identify 1-2 primary win conditions by answering:

   • What specific game state ends the game in the deck's favor?
   • What is the earliest realistic turn the win condition can be achieved?
   • What cards are essential for the win condition to function?

5. State the archetype selection and win condition in this format:

   • Archetype: [Aggro/Control/Combo/Midrange/Tempo]
   • Win Condition: [Specific description of how the deck wins]
   • Key Cards: [2-4 cards that enable the win condition]

Expected: A clear archetype with defined win conditions stated in the specified format. The strategy is specific enough to guide card selection.

On failure:

• If the user is unsure about archetype preference, present the top 3 meta archetypes with one-sentence summaries and ask them to pick
• If the format is unclear, search for current rotation/ban list and present the most common competitive format
• If no archetype feels right after research, identify the 3 strongest individual cards legal in the format and build around those as "good stuff" midrange

Step 2: Build the Core

Select the cards that define the deck's strategy using search tools to identify current staples.

1. Research the core engine cards:

   • Use WebSearch to find "[archetype] [game] [format] deck list" and "[key card name] deck [current year]"
   • Identify 12-20 cards that directly enable the win condition
   • List maximum legal copies of each core card (typically 3-4 copies per card depending on game rules)
   • Verify each core card is legal in the specified format via search or card database

2. Add support cards (8-15 cards) by searching for:

   • Card draw, search, or tutor effects that find core pieces
   • Protection effects (counters, shields, prevention)
   • Setup cards that accelerate the win condition
   • Filter effects (cards that dig through the deck)

3. Add interaction cards (8-12 cards):

   • Search for "[format] removal" and "[format] disruption" for the specific game
   • Include answers to common threats in the current meta
   • Balance between proactive disruption and reactive answers based on archetype

4. Fill the resource base based on game:

   • MTG: Use WebSearch to find "[archetype] land count [format]" or use 24-26 lands for 60-card decks
   • Pokemon: Research energy requirements for key attackers; typically 8-12 basic energy + 2-4 special energy
   • FaB: Balance pitch values (aim for 20-25 red, 15-20 yellow, 10-15 blue in 60-card deck)

5. Format the deck list as:

   CORE ENGINE (X cards):
   - Card Name x[quantity]
   - ...
   
   SUPPORT (X cards):
   - Card Name x[quantity]
   - ...
   
   INTERACTION (X cards):
   - Card Name x[quantity]
   - ...
   
   RESOURCES (X cards):
   - Card Name x[quantity]
   - ...
   

Expected: A complete deck list organized by function, at or near minimum deck size. Each section lists card names with quantities. The total card count is clearly stated.

On failure:

• If the deck exceeds minimum deck size by >5 cards: Identify the 5 lowest-impact support cards and remove them
• If the core engine requires >25 cards: Consolidate by keeping only cards that appear in 70%+ of online deck lists found in search
• If a key card is banned/illegal: Search for "[card name] replacement [format]" and substitute with the most commonly suggested alternative
• If budget constraints are violated: Search for "budget [archetype] [game]" and replace expensive cards with budget alternatives

Step 3: Analyze the Curve

Verify the deck's resource distribution supports its strategy with quantitative analysis.

1. Calculate and display the cost curve breakdown:

   • Count cards at each cost point (0, 1, 2, 3, 4, 5+)
   • Present as a simple text histogram or list
   • Example format: "Cost 0: 4 cards | Cost 1: 12 cards | Cost 2: 16 cards..."

2. Validate curve against archetype targets:

   • Aggro: 40%+ of non-resource cards should cost 1-2; <10% should cost 5+
   • Midrange: Peak at costs 2-3 (30-35% of non-resource cards); 15-20% at 4-5
   • Control: Flat distribution with 25% at 1-2, 25% at 3-4, 20% at 5+
   • Combo: 50%+ of cards at the combo's key cost points (typically 2-4)

3. Analyze resource distribution by game:

   • MTG: Calculate color pie (count mana symbols on cards; land count should match color intensity)
   • Pokemon: Count energy requirements per type; ensure energy base covers highest-cost attack
   • FaB: Count pitch values; verify hero's weapon requirements are met

4. Check card type ratios:

   • Non-resource cards should break down approximately:
     • Creatures/Attackers: 40-50%
     • Spells/Trainers/Actions: 30-40%
     • Other: 10-20%

5. Identify curve problems by flagging:

   • Costs with 0 cards (potential gaps)
   • Costs with >30% of non-resource cards (potential clumping)
   • Any 5+ cost cards in an aggro deck
   • <15% early plays (cost 1-2) in any archetype

Expected: A curve analysis showing the distribution at each cost point, identified deviations from archetype targets, and a clear statement of whether the curve supports the strategy.

On failure:

• If curve peaks at wrong cost for archetype: Replace cards at the wrong cost with cheaper/more expensive alternatives from the same functional category
• If color/resource requirements exceed base capacity: Add more resources of the strained type, or replace the most color-intensive card with a single-color alternative
• If gaps exist at critical costs (no 2-drops in midrange): Search "[format] best 2-drop [game]" and add 2-3 cards from results
• If too many high-cost cards: Cut 5+ cost cards down to 1-2 copies or replace with lower-cost alternatives that serve similar functions

Step 4: Meta-Game Positioning

Evaluate the deck against the expected field using current tournament data.

1. Research the current meta:

   • Search for "[game] [format] meta [current month year]" or "[game] [format] tier list [current season]"
   • Identify the top 5 most played decks with their approximate meta share percentages
   • Note the dominant archetype of each (aggro, control, combo, etc.)

2. Evaluate matchups systematically:

   • For each of the top 5 decks, assess: Is it favorable (+1), even (0), or unfavorable (-1)?
   • Document the reasoning in one sentence per matchup (e.g., "Aggro loses to our early removal suite")
   • If unsure about a matchup, search "[your archetype] vs [their archetype] [game] [format]"

3. Calculate weighted positioning:

   • Multiply each matchup score by the opponent's meta share percentage
   • Sum to get expected win rate against the field
   • Format: "Expected win rate: X% (calculated from weighted matchups)"

4. Present matchup analysis as:

   META POSITIONING ANALYSIS:
   Deck 1 (XX% of meta): [Favorable/Even/Unfavorable] - [reason]
   Deck 2 (XX% of meta): [Favorable/Even/Unfavorable] - [reason]
   ...
   Expected win rate: XX%
   Positioning: [Strong/Moderate/Weak]
   

5. If positioning is poor (<55% expected win rate):

   • Identify the 2 worst matchups
   • Search for "[archetype] sideboard [opposing deck]" or "[archetype] tech cards vs [strategy]"
   • Flag interaction slots that could be swapped to improve these matchups

Expected: A formatted matchup table showing the top 5 decks, their meta share, matchup assessment with reasoning, calculated expected win rate, and positioning verdict.

On failure:

• If current meta data is unavailable: State "Meta data unavailable — building for versatility" and ensure the interaction package includes at least 2 cards effective against each major archetype (aggro, control, combo)
• If the deck shows <50% expected win rate against top 5: Recommend a different archetype or major strategy pivot, explaining which 2-3 cards to swap first
• If specific matchup data can't be found: Use archetype-level analysis (e.g., "Aggro generally beats Combo, loses to Control") and note this is theoretical

Step 5: Build the Sideboard

Construct sideboard/side deck for format-specific adaptation if the format supports it.

1. First, verify the format supports sideboards:

   • MTG: 15-card sideboard allowed (most Constructed formats)
   • Pokemon TCG: No sideboard in most formats — skip this step
   • FaB: Sideboard size varies by format — search "[format] sideboard rules"
   • If sideboard not applicable: State "[Format] does not use sideboards — proceeding to validation"

2. For each unfavorable matchup identified in Step 4:

   • Search for "[your archetype] sideboard guide [opposing archetype] [game]"
   • Identify 2-4 cards that specifically counter that strategy
   • Prioritize cards that:
     • Directly answer the opponent's key cards
     • Can be cast through the opponent's disruption
     • Don't require significant curve adjustments

3. Format the sideboard with explicit swap instructions:

   SIDEBOARD (X cards):
   Card Name x[quantity]
     - Against: [List specific matchups]
     - Replaces: [Card(s) from main deck]
     - Reason: [Why this improves the matchup]
   

4. Verify each sideboard card meets efficiency criteria:

   • Covers at least 2 different matchups, OR
   • Is so critical to one matchup that it single-handedly flips it from unfavorable to favorable
   • Does not increase the deck's average converted mana cost by >0.5 when boarded in

5. Count and validate:

   • Total sideboard cards ≤ format limit
   • Every card has documented "Against" and "Replaces" fields
   • At least one card addresses each unfavorable matchup from Step 4

Expected: A formatted sideboard list with each card showing: quantity, applicable matchups, specific main deck cards it replaces, and reasoning. Total count within format limits.

On failure:

• If sideboard exceeds format limit: Remove the card with the narrowest matchup coverage first
• If a sideboard card only addresses one fringe deck: Replace it with a card that covers that deck plus another matchup
• If sideboard can't address an unfavorable matchup: Flag this as a deck strategy issue, not a sideboard issue — recommend 2-3 main deck swaps to improve that matchup instead
• If no sideboard guides or data available: Build a "generic" sideboard with 2-3 anti-aggro cards, 2-3 anti-control cards, and 2-3 versatile interaction pieces

Validation Checklist

Validate the completed deck before presenting to the user:

1. Archetype Clarity

   • Archetype is stated explicitly (Aggro/Control/Combo/Midrange/Tempo)
   • Win condition is described in one clear sentence
   • 2-4 key enabling cards are identified

2. Format Legality

   • Card count is at or above minimum, at or below maximum for the format
   • No cards on the format's ban list (verify via search if uncertain)
   • All cards are legal in the specified format (rotation status checked)

3. Card Role Definition

   • Each card is tagged as Core, Support, Interaction, or Resource
   • No card lacks a clear functional role
   • Core cards are at maximum legal copies

4. Curve Validation

   • Cost distribution histogram is provided
   • Archetype targets are met (see Step 3 thresholds)
   • No critical gaps (0 cards at a key cost) exist

5. Resource Adequacy

   • Resource count is within format norms (MTG: 24-26 lands; Pokemon: 8-12 energy; FaB: pitch balance)
   • Color/type requirements can be met by the resource base
   • Highest-cost card can be played consistently by the resource base

6. Meta Positioning

   • Top 5 meta decks are identified with sources
   • Matchup assessments include reasoning
   • Expected win rate is calculated and stated

Validation Failure Protocol: If any checklist item fails:

• State which item failed and why
• Either fix the issue and re-validate, OR
• Present the deck with the failure clearly noted and explain the limitation to the user

Common Pitfalls

Avoid these construction errors:

1. Too Many Win Conditions: A deck with 3+ distinct win conditions usually does none well. If more than 2 win conditions are identified, consolidate by removing the least consistent one and its supporting cards.

2. Curve Blindness: Adding powerful 5+ cost cards to an aggro deck, or too many 1-drops to control. If the curve analysis shows >10% deviation from archetype targets, flag this and propose specific swaps.

3. Ignoring the Meta: Building without checking the top 5 decks. If meta data is unavailable, state this explicitly and build for versatility with broad interaction.

4. Emotional Card Inclusion: Keeping "pet" cards that don't serve the strategy. When reviewing the deck, ask for each card: "Does this directly advance the win condition, protect it, or enable it?" If no, remove it.

5. Sideboard Afterthought: Filling sideboard with "leftover" cards. Each sideboard slot must have documented matchups and swap targets. If any sideboard card lacks this documentation, it must be removed or documented.

6. Over-Teching: Including >4 cards that only answer specific narrow strategies. If the interaction section contains narrow answers, replace half with broader interaction or main deck threats.

7. Resource Mismatch: Resource count that doesn't match archetype speed. Aggro decks with <20 lands in MTG, or control with >25, should be flagged immediately.

Output Contract

The final output must include:

1. Deck Summary (at the top):

   • Game, Format, Archetype stated clearly
   • Win condition described in one sentence
   • Total card count and positioning statement ("This deck is well-positioned against aggro but struggles against combo")

2. Deck List formatted as:

   CORE ENGINE (X cards):
   - Card Name x[quantity]
   
   SUPPORT (X cards):
   - Card Name x[quantity]
   
   INTERACTION (X cards):
   - Card Name x[quantity]
   
   RESOURCES (X cards):
   - Card Name x[quantity]
   

3. Curve Analysis:

   • Text histogram showing card count at each cost
   • Statement of whether curve supports archetype

4. Meta Positioning:

   • List of top 5 meta decks with matchup assessments
   • Expected win rate calculation

5. Sideboard (if applicable):

   • Formatted list with "Against" and "Replaces" for each card

6. Validation Note:

   • Statement: "This deck has been validated against the checklist in this skill"
   • Or, if validation failed: "Validation note: [specific item failed] — [explanation]"

7. Next Steps (brief):

   • 1-2 sentences suggesting how to test the deck or what to watch for in early games

Related Skills

• grade-tcg-card — Card condition assessment for tournament legality and collection value
• manage-tcg-collection — Inventory management for tracking which cards are available for deck building

Next Steps

After deck construction, consider these follow-up actions:

1. Test the deck — Play test games focusing on the first 3 turns to verify curve smoothness and mulligan decisions.

2. Evaluate sideboard performance — Track which sideboard cards actually get boarded in during testing; remove unused slots.

3. Iterate on meta shifts — Return to Step 4 after 2-4 weeks of play to reassess positioning if the meta changes.

4. Expand your collection — If budget constraints prevented optimal card choices, use manage-tcg-collection to track needed acquisitions.

5. Prepare for tournament — Use grade-tcg-card to verify all cards are tournament-legal condition before competition.