How We Automate Social Media Posts with Custom AI Assistants

StoryAngled Team
June 8, 2025
6 minutes

Most AI tools for social media promise efficiency. They generate captions, schedule posts, and sometimes even analyze engagement. But here’s the problem: they all sound the same.

Whether you’re using Buffer’s AI assistant, SocialBee, or Jasper, you’re getting generic output — something that resembles content but lacks strategy, voice, or depth.

Why? Because these tools are built for the masses. They’re not trained on your tone, your audience, or your product positioning. They guess. And when your marketing is just a bunch of AI guesses, people scroll right past it.

We ran into this wall too. As a content agency, we needed automation — but not at the cost of originality or performance. So instead of relying on generalist tools, we built our own system of custom AI assistants — each one built for a specific content task and trained on our tone, our structure, and our client goals.

They don’t just automate the post. They automate the thinking behind the post.

In this article, we’ll show you exactly how we did it — step-by-step. Starting with the most important piece: knowing what job you want your assistant to do.

Define a Clear Use Case for Each Assistant

The biggest mistake most people make when building AI assistants? They try to make one tool do everything.

Don’t.

The real power comes from building specialists, not generalists. Each assistant should solve one clear, repeatable content bottleneck — the kind that slows you down or burns you out week after week.

Ask yourself:

  • What kind of content do I create the most?

  • Where do I spend the most time unnecessarily?

  • What part of that process feels repetitive, but still needs quality?

For us, that meant building assistants like:

  • LinkedIn Post Writer – for voice-aligned, authority-building social posts

  • Carousel Craftr – for scripting visual swipe posts using smart structure

  • Newsletter Writer – for story-driven emails with embedded CTAs

  • IDEA Repurposer – for breaking long-form content into short-form fragments

  • Demanding AI Editor – for rewriting weak drafts into high-performing posts

Each one handles one job — and they’re much more effective because of it.

By clearly defining a single use case per assistant, you can:

  • Write better prompts

  • Train them faster

  • Reuse them in scalable workflows

Next, we’ll show you how to actually build the prompt that turns your assistant into a thinking, decision-making machine — not just a text generator.

Build the Prompt Like a Content Brief

A prompt isn’t just a command. It’s a creative brief — and if you write it that way, your assistant will generate content that sounds strategic, intentional, and uniquely you.

Here’s what most people do:

“You are a helpful social media assistant. Write a LinkedIn post about consistency.”

Result: Generic, vague, forgettable.

Here’s what we do:

We build prompts with strategy baked in. That means structuring them with clarity and detail, so the assistant knows exactly how to write, who it’s writing for, and what “good” looks like.

Use This Prompt Structure:

  1. Role – Who is this assistant acting as? For example: “You are a punchy B2B content strategist.”

  2. Task – What exactly is it doing, and in what format? For example: “Turn founder pain points into high-performing LinkedIn posts.”

  3. Audience – Who is this content for? For example: “Busy solopreneurs who overthink content and want clarity.”

  4. Tone/Style Rules – Keep it consistent. For example: “Short, bold sentences. No fluff. Lists > paragraphs. No emojis.”

  1. Do Not Use List – Remove cringey AI language. For example: ❌ “Delve” ❌ “Unlock” ❌ “Supercharge”

  2. WEAK vs. FABULOUS Examples – This trains it fast.
WEAK: “Here’s how to stay consistent.”
FABULOUS: “If you only create when you're motivated, you’re building a hobby. Not a brand.”

Pro tip: Break long prompts into labeled sections

That helps the assistant parse structure better and maintain logic over longer outputs.

Once this prompt is locked in, you’ve got the skeleton. Now it’s time to add the soul: your voice, your formatting, and your standards.

Let’s get into personalization next.

Personalize Everything: Tone, Format, Structure

Even with a great prompt, your assistant won’t hit the mark until it learns how you sound — and how you structure ideas.

Generic AI content isn’t just about poor wording. It’s about missing the subtle details: how you open a post, how you break lines, how you ask questions, where you add rhythm.

That’s why personalization is non-negotiable.

Step 1: Extract Your Tone of Voice

Use a tool like a Tone of Voice Quiz or analyze your best-performing posts. Identify:

  • Sentence length

  • Use of humor, directness, or storytelling

  • Favorite formats (lists, questions, analogies, punchlines)

Add this to the prompt as:

“Tone: Witty but not snarky. Speaks like a founder with a content brain. Avoids buzzwords. Prioritizes clarity over cleverness.”

Step 2: Define Formatting Rules

Be specific:

  • Paragraphs = 2 lines max

  • Use dashes or line breaks to emphasize key points

  • Bold takeaways or hooks

  • No emojis unless it's for tone softening (and only at the end)

AI thrives on clear, enforceable rules. Set them.

Step 3: Create a “Banned Phrases” List

This is your AI content detox. Remove fluff like:

  • “Unlock your potential”

  • “In today’s fast-paced world…”

  • “Delve into these tips”

Put them in a “DO NOT USE” section in your prompt. It’s one of the fastest ways to sharpen output.

Step 4: Provide Real-World Samples

Give your assistant actual posts to learn from. Even better — show it what not to do.

Example:

“3 ways to build your brand”
“Your brand is built when no one’s watching. Not just when you post. Here’s how I’ve seen it work for 3 clients.”

This kind of comparison accelerates learning and consistency.

Now that your assistant has a brain and a voice, it’s time to give it memory — by building a knowledge base it can pull from.

Upload a Knowledge Base So It Remembers Your Best Ideas

Even the smartest assistant is limited if it can’t access your past content, key insights, or product positioning. Without memory, it repeats itself. Worse — it forgets what’s already worked.

That’s where a knowledge base comes in. It turns your assistant from a copy generator into a strategist.

Option 1: Use the GPT Builder “Knowledge” Module

If you're creating your assistant inside the GPT Builder (ChatGPT Pro), you can upload documents directly:

  1. Open the GPT Builder

  2. Go to the “Knowledge” section

  3. Upload PDFs, blogs, case studies, brand guidelines — anything you want the assistant to reference

The assistant will use these files to generate more context-aware, brand-aligned content.

Use cases:

  • Referencing your product benefits in every CTA

  • Recalling past high-performing headlines

  • Pulling stories or stats from old newsletters

Option 2: Use Vector Stores via the OpenAI Platform

If you're using OpenAI’s developer tools, you can build a Vector Store through the “Storage” tab.

Here’s how:

  1. Go to Platform.openai.com → Storage → Vector Stores

  2. Create a new store and upload all your content

  3. Attach that store to your assistant thread when running prompts

It will now semantically search your documents — meaning it can find relevant insights even if your prompt doesn’t match keywords exactly.

Best for:

  • Agencies managing multiple clients

  • Founders with tons of archived posts

  • Creators wanting deep content reuse without cluttering the prompt

Knowledge Upload Tips:

  • Tag files by type: [Blog], [Newsletter], [Carousel]

  • Organize by theme: [Lead Gen], [Positioning], [Personal Stories]

  • Refresh weekly with your top content (and results)

This turns your assistant into a source of original, on-brand ideas — not just another regurgitation engine.

Let’s close this out with how we connect all of this into a single, scalable system.

Build a Content Flywheel With Chained Assistants

One assistant is helpful. But when you connect multiple assistants in a workflow, you create a content flywheel — where one idea gets transformed into multiple high-quality assets with minimal friction.

This is how we generate weeks of content from a single insight.

Example Workflow: One Idea → Multi-Platform Execution

  1. Newsletter Writer → Start with a personal story or insight, structured into an email

  2. IDEA Repurposer → Break that newsletter into 3–5 short-form ideas using the IDEA framework (Insight, Data, Emotion, Aesthetics)

  3. Carousel Craftr → Turn one of those fragments into a visual carousel for LinkedIn or Instagram

  4. LinkedIn Content Assistant → Write a standalone CTA post or commentary on the original insight

  5. Demanding AI Editor → Polish everything to match your exact tone and clarity standards

Now, from just one newsletter idea, you’ve got:

  • 1 email

  • 1 carousel

  • 2–3 LinkedIn posts

  • A week of consistent, high-performing content

Why This Works:

  • Each assistant plays a focused role — like a well-trained team member

  • You stay in strategy mode while AI handles execution

  • Brand voice and messaging stay consistent across every format

Pro tip:

Use the same tone-of-voice prompt and knowledge base across all assistants to ensure continuity and alignment.

Once your system is built, content creation becomes modular, scalable, and aligned — even across platforms and formats.

Let’s wrap this up.

Final Thoughts

Social media automation doesn’t have to mean sacrificing quality or voice. When you build your own custom AI assistants — each designed for a specific task, trained on your tone, and backed by your best content — you get speed and strategy.

This system isn’t just about saving time. It’s about scaling your creativity without burning out.

If you'd like access to the exact AI assistants we use to automate social media content for our agency and our clients — including prompts, knowledge templates, and setup guides — click here to get instant access.

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