Make optional API key environments nonblocking

engine_test.go

@@ -981,13 +981,15 @@ func TestMissingCredentialsFailClearlyWhenProfileRequiresAuth(t *testing.T) {
 	const missingEnv = "PROMPTKIT_PUBLIC_AUTH_MISSING"
 	t.Setenv(missingEnv, "")
 
-	profileDir := t.TempDir()
-	writePublicProfileFileWithAPIKeyEnv(t, profileDir, "requires-auth", "http://localhost:8000/v1", "test-model", missingEnv)
 	engine, err := promptkit.NewEngine(promptkit.Config{
-		PromptDir:  frameworkPromptDir,
-		ProfileDir: profileDir,
-		SchemaDir:  frameworkSchemaDir,
-	})
+		PromptDir: frameworkPromptDir,
+		SchemaDir: frameworkSchemaDir,
+	}, promptkit.WithProfiles(promptkit.Profile{
+		ID:             "requires-auth",
+		Endpoint:       "http://localhost:8000/v1",
+		Model:          "test-model",
+		APIKeyRequired: true,
+	}))
 	if err != nil {
 		t.Fatalf("expected engine construction to succeed, got %v", err)
 	}
@@ -995,6 +997,7 @@ func TestMissingCredentialsFailClearlyWhenProfileRequiresAuth(t *testing.T) {
 	_, err = engine.Prepare(context.Background(), promptkit.RunRequest{
 		PromptID:  frameworkMarkdownSummaryPromptID,
 		ProfileID: "requires-auth",
+		Execution: &promptkit.ExecutionTargetOverride{APIKeyEnv: missingEnv},
 		Inputs: map[string]promptkit.ArtifactRef{
 			"transcript": promptkit.Inline("Rin opens the gate."),
 			"glossary":   promptkit.Inline("gate: A guarded passage."),