Escape GT binary paths in JSON hook templates

Author: seanwessmith

internal/hooks/installer.go

@@ -150,12 +150,28 @@ func resolveAndSubstitute(provider, hooksFile, role string) ([]byte, error) {
 
 	if bytes.Contains(content, []byte("{{GT_BIN}}")) {
 		gtBin := resolveGTBinary()
+		if isSettingsFile(hooksFile) {
+			gtBin = jsonTemplateStringValue(gtBin)
+		}
 		content = bytes.ReplaceAll(content, []byte("{{GT_BIN}}"), []byte(gtBin))
 	}
 
 	return content, nil
 }
 
+// jsonTemplateStringValue escapes a string for insertion into an existing JSON
+// string literal template. json.Marshal adds surrounding quotes, so strip them.
+func jsonTemplateStringValue(value string) string {
+	encoded, err := json.Marshal(value)
+	if err != nil {
+		return value
+	}
+	if len(encoded) >= 2 {
+		return string(encoded[1 : len(encoded)-1])
+	}
+	return value
+}
+
 // writeTemplate resolves a template, substitutes placeholders, and writes it to targetPath.
 func writeTemplate(provider, role, hooksFile, targetPath string) error {
 	content, err := resolveAndSubstitute(provider, hooksFile, role)

internal/hooks/installer_test.go

@@ -281,6 +281,19 @@ func TestSyncForRole_GeminiWithGTBinSubstitution(t *testing.T) {
 	}
 }
 
+func TestJSONTemplateStringValue_EscapesWindowsPath(t *testing.T) {
+	value := `C:\Users\sws\bin\gt.exe`
+	escaped := jsonTemplateStringValue(value)
+
+	var decoded string
+	if err := json.Unmarshal([]byte(`"`+escaped+`"`), &decoded); err != nil {
+		t.Fatalf("json.Unmarshal escaped value: %v", err)
+	}
+	if decoded != value {
+		t.Fatalf("decoded value = %q, want %q", decoded, value)
+	}
+}
+
 func TestInstallForRole_SettingsDirVsWorkDir(t *testing.T) {
 	settingsDir := t.TempDir()
 	workDir := t.TempDir()