feat(agy): add gemini-3.8-flash default preference and fallback support

README.md

@@ -194,7 +194,7 @@ with category `"model"`. Clients can switch models by calling `session/set_confi
 Unknown model values and unsupported reasoning efforts return an error from
 `session/set_config_option`. If `AGY_MODEL` is set to an unknown value, the wrapper
 logs a warning and falls back to the catalog default (preferring
-`google/gemini-3.6-flash`, then `google/gemini-3.5-flash`).
+`google/gemini-3.8-flash`, then `google/gemini-3.7-flash`, then `google/gemini-3.6-flash`).
 
 ## Supported ACP Methods
 

internal/agy/models.go

@@ -45,6 +45,9 @@ type ModelCatalog struct {
 }
 
 var fallbackModelIDs = []string{
+	"gemini-3.8-flash-high",
+	"gemini-3.8-flash-medium",
+	"gemini-3.8-flash-low",
 	"gemini-3.7-flash-high",
 	"gemini-3.7-flash-medium",
 	"gemini-3.7-flash-low",
@@ -447,7 +450,7 @@ func pickDefaultEffort(native map[string]string) string {
 }
 
 func pickDefaultModel(profiles []ModelProfile) string {
-	for _, preferred := range []string{"google/gemini-3.7-flash", "google/gemini-3.6-flash", "google/gemini-3.5-flash"} {
+	for _, preferred := range []string{"google/gemini-3.8-flash", "google/gemini-3.7-flash", "google/gemini-3.6-flash", "google/gemini-3.5-flash"} {
 		for _, profile := range profiles {
 			if profile.CanonicalID == preferred {
 				return preferred

internal/agy/models_test.go

@@ -86,7 +86,7 @@ func TestModelCatalogFallback(t *testing.T) {
 	if err := catalog.EnsureLoaded(context.Background()); err != nil {
 		t.Fatal(err)
 	}
-	if got := catalog.DefaultModelID(); got != "google/gemini-3.7-flash" {
+	if got := catalog.DefaultModelID(); got != "google/gemini-3.8-flash" {
 		t.Fatalf("fallback default = %q", got)
 	}
 }
@@ -121,7 +121,6 @@ func TestModelCatalogRetryAfterTransientFailure(t *testing.T) {
 	}
 }
 
-
 func writeModelsScript(t *testing.T, output string) string {
 	t.Helper()
 	dir := t.TempDir()
@@ -139,11 +138,14 @@ func writeModelsScript(t *testing.T, output string) string {
 		return path
 	}
 	path := filepath.Join(dir, "agy-models.sh")
-	content := "#!/bin/sh\n"
-	for _, line := range lines {
-		content += "echo " + line + "\n"
-	}
-	if err := os.WriteFile(path, []byte(content), 0755); err != nil {
+	var b strings.Builder
+	b.WriteString("#!/bin/sh\ncat <<'EOF'\n")
+	if output != "" {
+		b.WriteString(strings.TrimSuffix(output, "\n"))
+		b.WriteString("\n")
+	}
+	b.WriteString("EOF\n")
+	if err := os.WriteFile(path, []byte(b.String()), 0755); err != nil {
 		t.Fatal(err)
 	}
 	return path
@@ -175,4 +177,28 @@ func TestModelCatalogDiscoverTSVWithPreamble(t *testing.T) {
 	}
 }
 
-
+func TestModelCatalogDiscoverGemini38Flash(t *testing.T) {
+	output := "Fetching available models...\ngemini-3.8-flash-high\tGemini 3.8 Flash (High)\ngemini-3.8-flash-medium\tGemini 3.8 Flash (Medium)\ngemini-3.8-flash-low\tGemini 3.8 Flash (Low)\n"
+	script := writeModelsScript(t, output)
+	catalog := NewStrictModelCatalog(script)
+	if err := catalog.EnsureLoaded(context.Background()); err != nil {
+		t.Fatalf("EnsureLoaded failed: %v", err)
+	}
+	models := catalog.Models()
+	if len(models) != 1 {
+		t.Fatalf("expected 1 canonical model, got %d: %#v", len(models), models)
+	}
+	if got := catalog.DefaultModelID(); got != "google/gemini-3.8-flash" {
+		t.Fatalf("expected default model google/gemini-3.8-flash, got %q", got)
+	}
+	for _, effort := range []string{"low", "medium", "high"} {
+		want := "gemini-3.8-flash-" + effort
+		if got, err := catalog.ResolveNative("google/gemini-3.8-flash", effort); err != nil || got != want {
+			t.Fatalf("ResolveNative(google/gemini-3.8-flash, %s) = %q, %v", effort, got, err)
+		}
+	}
+	efforts := catalog.SupportedEfforts("google/gemini-3.8-flash")
+	if len(efforts) != 3 {
+		t.Fatalf("expected 3 supported efforts, got %#v", efforts)
+	}
+}