fix: suppress misleading "Did you mean" suggestions

pkg/cmd/suggest.go

@@ -98,10 +98,22 @@ func jaroWinkler(a, b string) float64 {
 	return jaroDist + 0.1*prefixMatch*(1.0-jaroDist)
 }
 
+// suggestionThreshold is the minimum jaro-winkler similarity required before we
+// will print a "Did you mean" suggestion. Below this, the closest match is too
+// dissimilar to be a useful guess, so we stay silent rather than mislead.
+// 0.7 matches the boostThreshold used by jaroWinkler above — the prefix boost
+// only kicks in past that, so it's a natural "plausibly the same word" cutoff.
+const suggestionThreshold = 0.7
+
 // suggestCommand takes a list of commands and a provided string to suggest a
-// command name
+// command name. Returns an empty string when no command is sufficiently
+// similar; the upstream urfave/cli error formatter omits the suggestion clause
+// in that case.
 func suggestCommand(commands []*cli.Command, provided string) string {
-	distance := 0.0
+	if provided == "" {
+		return ""
+	}
+	distance := suggestionThreshold
 	var lineage []*cli.Command
 	for _, command := range commands {
 		for _, name := range command.Names() {
@@ -112,6 +124,9 @@ func suggestCommand(commands []*cli.Command, provided string) string {
 			}
 		}
 	}
+	if lineage == nil {
+		return ""
+	}
 
 	var parts []string
 	for _, command := range lineage {

pkg/cmd/suggest_test.go

@@ -0,0 +1,70 @@
+package cmd
+
+import (
+	"testing"
+
+	"github.com/urfave/cli/v3"
+)
+
+func TestSuggestCommand(t *testing.T) {
+	commands := []*cli.Command{
+		{Name: "create"},
+		{Name: "retrieve"},
+		{Name: "list"},
+		{Name: "delete"},
+		{Name: "chat:completions"},
+		{Name: "completions"},
+	}
+
+	tests := []struct {
+		name     string
+		provided string
+		want     string
+	}{
+		{
+			name:     "close typo suggests the corrected command",
+			provided: "creat",
+			want:     "Did you mean 'create'?",
+		},
+		{
+			name:     "near-exact suggests the corrected command",
+			provided: "chat:completion",
+			want:     "Did you mean 'chat:completions'?",
+		},
+		{
+			name:     "exact match still suggests itself",
+			provided: "create",
+			want:     "Did you mean 'create'?",
+		},
+		{
+			name:     "unrelated input returns no suggestion",
+			provided: "zzzzz",
+			want:     "",
+		},
+		{
+			name:     "low-similarity input returns no suggestion",
+			provided: "totallybogus",
+			want:     "",
+		},
+		{
+			name:     "empty input returns no suggestion",
+			provided: "",
+			want:     "",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			got := suggestCommand(commands, tc.provided)
+			if got != tc.want {
+				t.Errorf("suggestCommand(%q) = %q, want %q", tc.provided, got, tc.want)
+			}
+		})
+	}
+}
+
+func TestSuggestCommandEmptyCommands(t *testing.T) {
+	if got := suggestCommand(nil, "anything"); got != "" {
+		t.Errorf("suggestCommand(nil, %q) = %q, want empty string", "anything", got)
+	}
+}