diff --git a/internal/unifiedresources/canonical_identity.go b/internal/unifiedresources/canonical_identity.go
index bc89842669..838def2176 100644
--- a/internal/unifiedresources/canonical_identity.go
+++ b/internal/unifiedresources/canonical_identity.go
@@ -387,18 +387,47 @@ func firstTrimmed(values ...string) string {
 }
 
 func uniqueTrimmed(values ...string) []string {
-	seen := make(map[string]struct{}, len(values))
-	aliases := make([]string, 0, len(values))
+	// Canonical aliases usually contain only a handful of non-empty unique
+	// identities among many optional inputs. Do not allocate a map sized for
+	// every placeholder, or retain that capacity in each row's alias slice.
+	// A bounded stack scan handles the common case; larger vocabularies use
+	// the same lowercased-key map semantics without quadratic growth.
+	var smallKeys [8]string
+	var seen map[string]struct{}
+	aliases := make([]string, 0, min(len(values), len(smallKeys)))
 	for _, value := range values {
 		trimmed := strings.TrimSpace(value)
 		if trimmed == "" {
 			continue
 		}
 		key := strings.ToLower(trimmed)
-		if _, ok := seen[key]; ok {
-			continue
+		if seen != nil {
+			if _, ok := seen[key]; ok {
+				continue
+			}
+		} else {
+			duplicate := false
+			for _, previous := range smallKeys[:len(aliases)] {
+				if previous == key {
+					duplicate = true
+					break
+				}
+			}
+			if duplicate {
+				continue
+			}
+			if len(aliases) < len(smallKeys) {
+				smallKeys[len(aliases)] = key
+			} else {
+				seen = make(map[string]struct{}, min(len(values), 64))
+				for _, previous := range smallKeys {
+					seen[previous] = struct{}{}
+				}
+			}
+		}
+		if seen != nil {
+			seen[key] = struct{}{}
 		}
-		seen[key] = struct{}{}
 		aliases = append(aliases, trimmed)
 	}
 	return aliases
diff --git a/internal/unifiedresources/canonical_identity_allocation_test.go b/internal/unifiedresources/canonical_identity_allocation_test.go
new file mode 100644
index 0000000000..15be6207be
--- /dev/null
+++ b/internal/unifiedresources/canonical_identity_allocation_test.go
@@ -0,0 +1,85 @@
+package unifiedresources
+
+import (
+	"fmt"
+	"math/rand"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+// Independent original implementation. Lowercasing is intentionally not
+// EqualFold: those operations differ for some Unicode identities.
+func uniqueTrimmedMapReference(values ...string) []string {
+	seen := make(map[string]struct{}, len(values))
+	aliases := make([]string, 0, len(values))
+	for _, value := range values {
+		trimmed := strings.TrimSpace(value)
+		if trimmed == "" {
+			continue
+		}
+		key := strings.ToLower(trimmed)
+		if _, ok := seen[key]; ok {
+			continue
+		}
+		seen[key] = struct{}{}
+		aliases = append(aliases, trimmed)
+	}
+	return aliases
+}
+func TestCanonicalAliasesBoundedScanMatchesOriginalMap(t *testing.T) {
+	cases := [][]string{nil, {}, {"", "  ", "\t"}, {" Host ", "host", "HOST", "other"}, {"K", "K", "k", "İ", "i", "Σ", "σ", "ς", "ſ", "S", "s"}}
+	for _, count := range []int{7, 8, 9, 16, 128, 1024} {
+		var values []string
+		for i := 0; i < count; i++ {
+			value := fmt.Sprintf("Alias-%d", i)
+			values = append(values, " ", value, strings.ToLower(value), " "+value+" ")
+		}
+		cases = append(cases, values)
+	}
+	rng := rand.New(rand.NewSource(2199))
+	alphabet := []string{"", " ", "Host", "host", "HOST", "agent:lab", " vm:100 ", "K", "K", "İ", "i", "Σ", "σ", "ς", "ſ", "S"}
+	for i := 0; i < 200; i++ {
+		values := make([]string, rng.Intn(80))
+		for j := range values {
+			values[j] = alphabet[rng.Intn(len(alphabet))]
+		}
+		cases = append(cases, values)
+	}
+	for i, values := range cases {
+		got, want := uniqueTrimmed(values...), uniqueTrimmedMapReference(values...)
+		if !reflect.DeepEqual(got, want) {
+			t.Fatalf("case %d: got %q, want %q", i, got, want)
+		}
+		if len(values) > 0 && len(got) > 0 {
+			original := values[0]
+			got[0] = "caller-edit"
+			if values[0] != original {
+				t.Fatal("aliases share caller storage")
+			}
+		}
+	}
+}
+func TestCanonicalAliasesSmallVocabularyAvoidsPlaceholderMap(t *testing.T) {
+	values := []string{"lab", "", "", "LAB", "agent:lab", "", "", "agent:lab", "lab.example", "", "", "", "", "lab.example", "", ""}
+	optimized := testing.AllocsPerRun(100, func() { _ = uniqueTrimmed(values...) })
+	original := testing.AllocsPerRun(100, func() { _ = uniqueTrimmedMapReference(values...) })
+	if optimized >= original {
+		t.Fatalf("common alias list allocations %.0f, original %.0f", optimized, original)
+	}
+	t.Logf("same alias vocabulary: allocations %.0f -> %.0f", original, optimized)
+}
+func BenchmarkCanonicalAliasesVocabulary(b *testing.B) {
+	for _, size := range []int{4, 8, 9, 128} {
+		values := make([]string, 0, size*3)
+		for i := 0; i < size; i++ {
+			values = append(values, fmt.Sprintf("alias-%d", i), "", fmt.Sprintf("ALIAS-%d", i))
+		}
+		b.Run(fmt.Sprint(size), func(b *testing.B) {
+			b.ReportAllocs()
+			for i := 0; i < b.N; i++ {
+				_ = uniqueTrimmed(values...)
+			}
+		})
+	}
+}