Centralize output contract validation

internal/promptdef/repository_test.go

@@ -479,6 +479,77 @@ output:
 	}
 }
 
+func TestPromptRepositoriesApplyOutputContractRules(t *testing.T) {
+	tests := []struct {
+		name           string
+		output         string
+		useFilesystem  bool
+		wantErr        bool
+		wantDiagnostic string
+		wantSchemaPath string
+	}{
+		{
+			name:           "operating-system source rejects unsupported format",
+			output:         "  format: binary\n  validation_mode: none\n",
+			useFilesystem:  true,
+			wantErr:        true,
+			wantDiagnostic: "format",
+		},
+		{
+			name:           "fs source rejects negative repair attempts",
+			output:         "  format: text\n  validation_mode: none\n  repair_attempts: -1\n",
+			wantErr:        true,
+			wantDiagnostic: "repair_attempts",
+		},
+		{
+			name:           "source normalization trims a valid schema path",
+			output:         "  format: json\n  validation_mode: json_schema\n  schema_path: ' schema.json '\n",
+			useFilesystem:  true,
+			wantSchemaPath: "schema.json",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			data := `id: output-contract
+version: "1"
+messages:
+  - role: user
+    content: test
+output:
+` + tt.output
+
+			var repo Repository
+			if tt.useFilesystem {
+				dir := t.TempDir()
+				writePromptTestFile(t, filepath.Join(dir, "output-contract.yaml"), data)
+				repo = NewFilesystemRepository(dir)
+			} else {
+				repo = NewFSRepository(fstest.MapFS{
+					"output-contract.yaml": &fstest.MapFile{Data: []byte(data)},
+				}, ".")
+			}
+
+			got, err := repo.GetPromptDefinition(context.Background(), "output-contract", "")
+			if tt.wantErr {
+				if !errors.Is(err, ErrInvalidPromptDefinition) {
+					t.Fatalf("expected ErrInvalidPromptDefinition, got %v", err)
+				}
+				if !strings.Contains(err.Error(), tt.wantDiagnostic) {
+					t.Fatalf("expected error containing %q, got %v", tt.wantDiagnostic, err)
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("load prompt definition: %v", err)
+			}
+			if got.Validation.SchemaPath != tt.wantSchemaPath {
+				t.Fatalf("schema path = %q, want %q", got.Validation.SchemaPath, tt.wantSchemaPath)
+			}
+		})
+	}
+}
+
 func assertCacheControl(t *testing.T, got *domain.CacheControl, wantType domain.CacheControlType, wantTTL string) {
 	t.Helper()
 	if got == nil {