if (sources == null || sources.isEmpty()) {
            return buildTruncatedContent(msg, summaryMaxChars);
        }
        final int maxSuffixLen = Math.max(0, summaryMaxChars / 4);
        final String suffix = buildSourceTitlesSuffix(sources, maxSuffixLen);
        if (suffix.isEmpty()) {
            return buildTruncatedContent(msg, summaryMaxChars);
        }
        final String content = msg.getContent();