I Built a Psychology-Based Copy Analyzer. Here’s What 200+ Real B2B Messages Taught Me.

For the past year, I've been building COS — a tool that uses Big Five personality psychology to analyze B2B communications. Not grammar. Not readability. Personality coverage.

The premise is simple: every piece of copy you write passes through an invisible psychological filter in your reader's brain. Their personality type determines what resonates, what triggers skepticism, and what they ignore entirely. Most B2B copy only connects with 1-2 of the 5 major personality types, leaving 60-80% of potential buyers unmoved.

I wanted to build a tool that could actually measure this. Here's what I learned along the way.

Insight 1: "Good Writing" and "Effective Writing" Are Different Things

This was the biggest surprise. Copy that scored perfectly on Grammarly and Hemingway regularly scored below 30% on personality coverage. Technically flawless. Psychologically one-dimensional.

The reverse was also true — some rough-draft emails with typos scored 70%+ because the writer instinctively covered multiple personality types. They used specifics (Conscientiousness), showed warmth (Agreeableness), included proof (Neuroticism), and painted a vision (Openness) — all without knowing the framework.

Good writing isn't enough. Effective writing reaches the right psychological triggers.

Insight 2: Every Industry Has a Default Personality Bias

• Tech/SaaS: Defaults to high Openness. "Innovative," "disruptive," "transform." Misses Conscientiousness (where are the numbers?) and Neuroticism (what if it breaks?).
• Finance/Enterprise: Defaults to high Conscientiousness. All metrics, no warmth. Misses Agreeableness (cold and transactional) and Openness (boring, even if credible).
• Coaching/Consulting: Defaults to high Agreeableness. Warm and relational but vague. Misses Conscientiousness (skeptics need proof) and Extraversion (where's the energy?).

Once you see the pattern, you can't unsee it. And you can fix it in minutes.

Insight 3: Small Changes Create Huge Swings

Adding one concrete metric can move your Conscientiousness score by 40+ points. Including a single "3 companies already did this" reference covers both social proof (Extraversion) and risk mitigation (Neuroticism) simultaneously.

The fixes are almost never rewrites. They're additions — filling gaps that were always there.

Insight 4: The Copy That "Feels Salesy" Is Usually Missing Safety

When people say copy "feels pushy" or "too salesy," they're usually describing a message that lacks Agreeableness (warmth, collaboration) and Neuroticism (reassurance, risk acknowledgment) signals. It's all push, no safety net.

Adding a single line like "No commitment needed — cancel anytime" or "Here's what to watch out for" can completely shift the feel without changing your core message.

What's Next

COS is live at semalytics.com. I'm offering a free trial so you can test it with your own copy. Paste in any email, landing page, LinkedIn post, or sales outreach and see what comes back.

I'll be sharing more findings here as the data grows. If you work in B2B and write things that need to persuade people, I'd love to hear what COS finds in your copy.