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TL;DR / Key Takeaways

  • Generic AI prompts produce generic “AI-sounding” content (words like “delve”, “tapestry”, “landscape”).
  • XML is the best format for System Prompts because LLMs parse tags strictly.
  • A single “Brand Voice XML” file can control tone, formatting, and banned words across all your automations.
  • We provide a free, copy-paste XML template you can adapt today.
If I read one more LinkedIn post that starts with “In the rapidly evolving landscape of…” I’m going to scream. We all know the problem. You ask ChatGPT or Claude to write a social media post, and it gives you something that is technically correct but completely soulless. It uses words nobody uses in real life. It uses emojis like a 14-year-old in 2012. The solution isn’t “better prompt engineering” in the sense of writing longer paragraphs of text. The solution is structured data. Specifically, XML.

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Why XML?

Large Language Models (LLMs) are trained on code. They understand structure. When you write a paragraph of text describing your tone, the model has to “guess” which parts are rules and which parts are just suggestions. When you use XML tags like <tone>, <banned_words>, and <formatting>, you are speaking the model’s native language. You are creating strict boundaries that the model is much less likely to ignore.

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The “Brand Voice XML” Template

Here is a stripped-down, anonymized version of the actual XML file we use at bundle.social to generate content. Copy this, save it as brand_voice.xml, and fill in your details. 
<?xml version="1.0" encoding="UTF-8"?>
<brand_profile>
  <meta>
    <company_name>Acme Corp</company_name>
    <industry>SaaS / Developer Tools</industry>
    <target_audience>Senior Developers and CTOs</target_audience>
  </meta>

  <!-- SEO CONFIGURATION -->
  <seo>
    <keyword_placement>
      <location priority="1">Page title</location>
      <location priority="2">First sentence</location>
      <location priority="3">H2 headers</location>
    </keyword_placement>
    <internal_linking>
      <rule>Link to relevant docs pages when technical terms are mentioned.</rule>
      <rule>Max 3 internal links per post.</rule>
    </internal_linking>
  </seo>

  <!-- CONTENT STRUCTURE -->
  <structure>
    <opening>
      <rule>TL;DR list at the very top.</rule>
      <rule>Hook in the first sentence.</rule>
      <rule>No fluff or "In this article we will..." intros.</rule>
    </opening>
    <body>
      <rule>H2 for main sections.</rule>
      <rule>H3 for subsections.</rule>
      <rule>Callout boxes for warnings or tips.</rule>
    </body>
  </structure>

  <!-- VOICE & TONE -->
  <voice>
    <primary>Technical, direct, pragmatic</primary>
    <secondary>Helpful, slightly witty</secondary>
    <avoid>Salesy, corporate jargon, overly enthusiastic</avoid>
    <rule>Write like a senior engineer talking to a peer.</rule>
    <rule>Use "I've seen this..." to add personal credibility.</rule>
  </voice>

  <!-- AUTHORITY & CREDIBILITY -->
  <authority>
    <rule>Don't preach. Show, don't just tell.</rule>
    <rule>Use specific numbers and data points whenever possible.</rule>
    <rule>Reference real-world engineering constraints (latency, cost, maintenance).</rule>
  </authority>

  <!-- LANGUAGE RULES -->
  <language>
    <style>
      <jargon_level>Medium-High (assume the reader is technical)</jargon_level>
      <swearing>Rare, mild only (e.g., "s**t happens"), never directed at the reader.</swearing>
      <emojis>0-2 per post max. Never use "rocket" or "gem" emojis.</emojis>
    </style>
    <abbreviations>
      <allowed>API, SaaS, CTO, CI/CD, ROI, tbh, imo</allowed>
      <rule>Use commonly understood tech abbreviations freely.</rule>
    </abbreviations>
  </language>

  <!-- CREDIBILITY INDICATORS -->
  <credibility>
    <source_linking>
      <rule>Link to primary documentation, not third-party tutorials.</rule>
      <rule>Always date-check sources (avoid anything older than 2024 for AI/Social).</rule>
    </source_linking>
    <personal_experience>
      <rule>Mention "production" environments or "scaling" issues.</rule>
      <rule>Share specific outcomes (e.g., "saved 10 hours", "cut costs by 40%").</rule>
    </personal_experience>
  </credibility>

  <!-- FORMATTING RULES -->
  <formatting>
    <structure>
      <rule>Short paragraphs (1-3 sentences).</rule>
      <rule>Use bullet points for lists.</rule>
      <rule>No hashtags in the middle of sentences.</rule>
    </structure>
    <syntax>
      <rule>Use "we" instead of "I" for company announcements.</rule>
      <rule>No exclamation marks unless absolutely necessary.</rule>
    </syntax>
  </formatting>

  <!-- AI READABILITY & HUMANITY -->
  <llm_readability>
    <filler_filter>
      <rule>Delete vague transitions ("so now", "you might be wondering").</rule>
      <rule>No "inspiration strikes" language.</rule>
    </filler_filter>
    <questions>
      <rule>Rhetorical questions allowed only if answered immediately.</rule>
    </questions>
  </llm_readability>

  <!-- CALL TO ACTION -->
  <call_to_action>
    <style>Soft, helpful, non-pushy</style>
    <rule>Questions? Hit me up on Twitter.</rule>
    <rule>Try it out and let me know how it goes.</rule>
    <avoid>Click here, Sign up now, Limited time offer</avoid>
  </call_to_action>

  <!-- BANNED WORDS (The AI Filter) -->
  <banned_words>
    <word>delve</word>
    <word>landscape</word>
    <word>tapestry</word>
    <word>transformative</word>
    <word>game-changer</word>
    <word>cutting-edge</word>
    <word>unleash</word>
    <word>unlock</word>
    <word>elevate</word>
    <word>supercharge</word>
    <word>robust</word>
    <word>seamless</word>
    <word>paradigm</word>
    <word>holistic</word>
  </banned_words>

  <!-- CONTENT EXAMPLES (Few-Shot Prompting) -->
  <examples>
    <bad_example>
      "Unlock the power of our cutting-edge API to supercharge your workflow!"
    </bad_example>
    <good_example>
      "Our API handles rate limits automatically so you don't have to write retry logic."
    </good_example>
  </examples>
</brand_profile>

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How to use this XML

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Option 1: In ChatGPT / Claude (Projects)

If you use the “Projects” feature in Claude or ChatGPT, simply upload this brand_voice.xml file to your project knowledge. Then, your prompt can be as simple as:
“Write a LinkedIn post about our new feature based on the guidelines in brand_voice.xml”
The model will read the file and apply every rule strictly.

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Option 2: In n8n (Automated Workflows)

If you are building the social media automation workflow we discussed previously, this is a game changer.
  1. Upload your XML file to a URL (e.g., your website or a GitHub Gist) or store it in a Google Doc.
  2. In n8n, use an HTTP Request node (or Google Drive node) to fetch the file content.
  3. Pass the content into the System Message of your AI Agent node.
System Prompt Example: 
You are a social media manager for Acme Corp.
Strictly follow the brand guidelines provided in the XML context below.
Focus especially on the <banned_words> list.

<xml_context>
{{ $json.xml_content }}
</xml_context>

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Why this works better than “Custom Instructions”

Custom instructions are great, but they are limited in length and hard to version control. An XML file is a living document.
  • Version Control: You can commit it to Git.
  • Scalability: You can add new sections (e.g., <product_specs>) without breaking the existing structure.
  • Portability: You can use the same file across ChatGPT, n8n, Make, and your custom code.

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Summary

Stop letting AI define your voice. Define it yourself in code. By treating your brand voice as a dataset rather than a “vibe,” you regain control over your content quality. And you’ll never have to read the word “tapestry” in your own posts again.