Reveal tripled-in pets but keep the pick secret unless it buys.

internal/game/game.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"math/big"
 	"slices"
+	"strings"
 )
 
 // Tunable rules. The engine supports any player count >= 2; MinPlayers /
@@ -369,6 +370,17 @@ func (g *Game) sellCards(p *Player, cardIDs []string) error {
 	return nil
 }
 
+// hasBuyEffect reports whether a card carries any buy-triggered ability, which
+// means acquiring it does something visible to everyone.
+func hasBuyEffect(c Card) bool {
+	for _, e := range c.Effects {
+		if e.Trigger == TriggerBuy {
+			return true
+		}
+	}
+	return false
+}
+
 // TradeStart spends one coin and three same-suit pets from the player's deck
 // to reveal the top two cards of the next tier's deck. The player must then
 // call TradeChoose before anything else happens.
@@ -412,7 +424,14 @@ func (g *Game) TradeStart(playerID string, cardIDs []string) error {
 	}
 	p.Coins--
 	p.TripledThisRound = true
-	g.logf(p.Seat, "🔄", "%s traded in 3 %s pets for a tier %d pick.", p.Name, suit, nextTier)
+	// The discarded trio is public — everyone sees what was given up — even
+	// though the pet ultimately chosen stays secret (see TradeChoose).
+	names := make([]string, len(traded))
+	for i, c := range traded {
+		names[i] = c.Name
+	}
+	g.logf(p.Seat, "🔄", "%s traded in %s (%s) for a tier %d pick.",
+		p.Name, strings.Join(names, ", "), suit, nextTier)
 	g.Pending = &PendingTrade{
 		PlayerID: playerID,
 		Tier:     nextTier,
@@ -440,7 +459,15 @@ func (g *Game) TradeChoose(playerID string, pick int) error {
 	tierIdx := g.Pending.Tier - 1
 	g.ShopDecks[tierIdx] = append(g.ShopDecks[tierIdx], other)
 	g.Pending = nil
-	g.logf(p.Seat, "🔄", "%s picked %s from the trade.", p.Name, chosen.Name)
+	// The pick is secret — opponents never saw the two revealed options and
+	// can't see the deck. But a pet with a Buy ability performs it publicly, so
+	// we have to reveal that pet (its effect log names it anyway).
+	if hasBuyEffect(chosen) {
+		g.logf(p.Seat, "🔄", "%s's trade pick is %s %s — its buy ability triggers.",
+			p.Name, article(chosen.Name), chosen.Name)
+	} else {
+		g.logf(p.Seat, "🔄", "%s keeps their trade pick hidden.", p.Name)
+	}
 	// Pets obtained via the Triple action trigger their Buy effects.
 	g.applyShopTrigger(p, chosen, TriggerBuy)
 	g.advanceShopTurn()

internal/game/game_test.go

@@ -2,6 +2,7 @@ package game
 
 import (
 	"slices"
+	"strings"
 	"testing"
 )
 
@@ -225,6 +226,54 @@ func TestTradeTriggersTripleAndBuyEffects(t *testing.T) {
 	}
 }
 
+// A triple makes the three discarded pets public, but keeps the chosen pet
+// secret — unless it has a Buy ability, which performs publicly.
+func TestTradeVisibilityHidesPickUnlessBuyEffect(t *testing.T) {
+	logContains := func(g *Game, sub string) bool {
+		for _, e := range g.Log {
+			if strings.Contains(e.Text, sub) {
+				return true
+			}
+		}
+		return false
+	}
+	trade := func(g *Game, pick Card) *Game {
+		p := current(g)
+		var ids []string
+		for range 3 {
+			c := g.pet("Newt", 1)
+			c.Suit = SuitBlue
+			p.Deck = append(p.Deck, c)
+			ids = append(ids, c.ID)
+		}
+		if err := g.TradeStart(p.ID, ids); err != nil {
+			t.Fatal(err)
+		}
+		g.Pending.Options[0] = pick
+		if err := g.TradeChoose(p.ID, 0); err != nil {
+			t.Fatal(err)
+		}
+		return g
+	}
+
+	// Discarded trio is named; an effect-less pick stays hidden.
+	g, _, _ := testGame(t)
+	trade(g, g.pet("SecretPet", 3))
+	if !logContains(g, "Newt") {
+		t.Fatal("the discarded pets should be public in the log")
+	}
+	if logContains(g, "SecretPet") {
+		t.Fatal("a pick with no buy ability must stay hidden")
+	}
+
+	// A pick with a Buy ability (Otter) is revealed.
+	g2, _, _ := testGame(t)
+	trade(g2, g2.realPet(t, "Otter"))
+	if !logContains(g2, "Otter") {
+		t.Fatal("a pick with a buy ability should be revealed in the log")
+	}
+}
+
 func TestBuyWormAddsTwoApples(t *testing.T) {
 	g, _, _ := testGame(t)
 	p := current(g)