diff --git a/coach/services/deck_generator.py b/coach/services/deck_generator.py
index 9773646..ae8f866 100644
--- a/coach/services/deck_generator.py
+++ b/coach/services/deck_generator.py
@@ -253,6 +253,9 @@ class DeckGeneratorV3:
         # Step 5: Check ownership and build enriched card list
         cards_with_status = self._check_ownership(raw_deck.get("cards", []))
 
+        # Step 5b: Fill basic lands to hit exactly 100 cards
+        cards_with_status = self._fill_basic_lands(cards_with_status, color_identity)
+
         # Step 6: Compute stats
         stats = self._compute_stats(cards_with_status)
 
@@ -319,6 +322,57 @@ class DeckGeneratorV3:
 
         return enriched
 
+    # ── Step 5b: Basic Land Fill ──────────────────────────────
+    _COLOR_TO_BASIC = {
+        'W': 'Plains', 'U': 'Island', 'B': 'Swamp',
+        'R': 'Mountain', 'G': 'Forest',
+    }
+    _BASIC_NAMES = set(_COLOR_TO_BASIC.values()) | {'Wastes'}
+
+    def _fill_basic_lands(
+        self,
+        cards: List[DeckCardWithStatus],
+        color_identity: List[str],
+        target_total: int = 100,
+    ) -> List[DeckCardWithStatus]:
+        """
+        Strip LLM-provided basics, then add the right number evenly
+        across the commander's colors to reach exactly target_total.
+        """
+        non_basics = [c for c in cards if c.name not in self._BASIC_NAMES]
+        current_total = sum(c.count for c in non_basics)
+        basics_needed = max(0, target_total - current_total)
+
+        if basics_needed == 0:
+            return non_basics
+
+        ci = [c.upper() for c in color_identity]
+        basic_names = [self._COLOR_TO_BASIC[c] for c in ci if c in self._COLOR_TO_BASIC]
+        if not basic_names:
+            basic_names = ['Wastes']
+
+        per_color = basics_needed // len(basic_names)
+        remainder = basics_needed % len(basic_names)
+
+        for i, bname in enumerate(basic_names):
+            qty = per_color + (1 if i < remainder else 0)
+            if qty > 0:
+                non_basics.append(DeckCardWithStatus(
+                    name=bname,
+                    count=qty,
+                    category='Land',
+                    role_tags=[],
+                    reason='Basic land for mana fixing',
+                    estimated_price_usd=0.10,
+                    owned=True,
+                    owned_qty=qty,
+                    status='owned',
+                ))
+
+        logger.info("Basic land fill: %d basics added across %d color(s)",
+                     basics_needed, len(basic_names))
+        return non_basics
+
     # ── Step 6: Smart Substitution ───────────────────────────
     def run_substitution(
         self,
diff --git a/lab_api.py b/lab_api.py
index 36a0c2d..7afa7dd 100644
--- a/lab_api.py
+++ b/lab_api.py
@@ -6318,6 +6318,73 @@ def _postprocess_deck_cards(cards: list[dict], color_identity: list[str] | None
     return processed
 
 
+# Color-to-basic-land mapping for deterministic fill
+_COLOR_TO_BASIC = {
+    'W': 'Plains',
+    'U': 'Island',
+    'B': 'Swamp',
+    'R': 'Mountain',
+    'G': 'Forest',
+}
+BASIC_LAND_NAMES = set(_COLOR_TO_BASIC.values()) | {'Wastes'}
+
+
+def _fill_basic_lands(cards: list[dict], color_identity: list[str] | None = None, target_total: int = 100) -> list[dict]:
+    """
+    Deterministically fill basic lands so the deck hits exactly target_total cards.
+
+    The LLM may list basics with wrong counts, duplicates, or omit them.
+    This function:
+      1. Strips all basic-land entries the LLM provided
+      2. Counts remaining cards (non-basics) and their total count
+      3. Computes how many basic land slots are needed
+      4. Distributes basics evenly across the commander's colors
+    """
+    # Separate basics from non-basics
+    non_basics = []
+    for card in cards:
+        name = card.get('name', '').strip()
+        if name not in BASIC_LAND_NAMES:
+            non_basics.append(card)
+
+    # Count total non-basic cards
+    non_basic_total = sum(c.get('count', 1) for c in non_basics)
+
+    # How many basic land copies we need
+    basics_needed = max(0, target_total - non_basic_total)
+
+    if basics_needed == 0:
+        return non_basics
+
+    # Determine which basics to use from color identity
+    ci = [c.upper() for c in (color_identity or [])]
+    basic_names = [_COLOR_TO_BASIC[c] for c in ci if c in _COLOR_TO_BASIC]
+    if not basic_names:
+        # Colorless commander — use Wastes
+        basic_names = ['Wastes']
+
+    # Distribute evenly, then add remainders one-by-one
+    per_color = basics_needed // len(basic_names)
+    remainder = basics_needed % len(basic_names)
+
+    for i, bname in enumerate(basic_names):
+        qty = per_color + (1 if i < remainder else 0)
+        if qty > 0:
+            non_basics.append({
+                'name': bname,
+                'count': qty,
+                'role': 'land',
+                'category': 'Land',
+                'role_tags': [],
+                'reason': 'Basic land for mana fixing',
+                'estimated_price_usd': 0.10,
+                'from_collection': False,
+                'is_basic': True,
+            })
+
+    return non_basics
+
+
 # ── Research Endpoint ─────────────────────────────────────────
 
 @app.post('/api/deck-research')
@@ -6567,6 +6634,8 @@ Build the deck as JSON. Prioritize collection cards when they fit the strategy."
     # Post-process cards
     if 'cards' in result and isinstance(result['cards'], list):
         result['cards'] = _postprocess_deck_cards(result['cards'], color_identity)
+        # Fill basic lands deterministically to hit exactly 100
+        result['cards'] = _fill_basic_lands(result['cards'], color_identity, target_total=100)
 
     # Compute real totals
     real_total = sum(c.get('estimated_price_usd', 0) * c.get('count', 1) for c in result.get('cards', []))
diff --git a/ui/deckgenerator.css b/ui/deckgenerator.css
index 73e5964..80f33dc 100644
--- a/ui/deckgenerator.css
+++ b/ui/deckgenerator.css
@@ -1152,6 +1152,19 @@
     font-size: 0.85rem;
 }
 
+.dg-card-count {
+    display: inline-block;
+    background: var(--accent, #6c63ff);
+    color: #fff;
+    border-radius: 4px;
+    padding: 1px 5px;
+    font-size: 0.7rem;
+    font-weight: 700;
+    margin-right: 2px;
+    min-width: 20px;
+    text-align: center;
+}
+
 .dg-card-row-roles {
     display: flex;
     gap: 3px;
diff --git a/ui/deckgenerator.js b/ui/deckgenerator.js
index f12f7cc..bd22790 100644
--- a/ui/deckgenerator.js
+++ b/ui/deckgenerator.js
@@ -406,7 +406,7 @@ const DeckGenerator = (() => {
             html += '<div class="dg-card-group">'
                 + '<div class="dg-group-header" data-type="' + type + '">'
                 + '<span class="dg-group-title">' + icon + ' ' + escHtml(type) + '</span>'
-                + '<span class="dg-group-count">' + groupCards.length + '</span>'
+                + '<span class="dg-group-count">' + groupCards.reduce(function(s,c){ return s + (c.count || 1); }, 0) + '</span>'
                 + '</div>'
                 + '<div class="dg-group-body" data-group="' + type + '">';
 
@@ -462,7 +462,7 @@ const DeckGenerator = (() => {
 
         return '<div class="dg-card-row dg-card-status-' + card.status + '">'
             + '<div class="dg-card-row-main">'
-            + '<span class="dg-card-row-name">' + escHtml(card.name) + '</span>'
+            + '<span class="dg-card-row-name">' + ((card.count || 1) > 1 ? '<span class="dg-card-count">' + card.count + 'x</span> ' : '') + escHtml(card.name) + '</span>'
             + '<span class="dg-card-row-roles">' + roleTags + '</span>'
             + statusBadge
             + price