Custom GPT - The new ChatGPT-5.1 is out. Is it any better?

Custom ChatGPT - The new ChatGPT-5.1 is out. Is it any better?

Table of contents

• What’s new in GPT-5.1
• First impressions after 24 hours
• The 7 personality modes
• Why custom instructions matter
• How recruiters can use GPT-5.1 to work smarter
• What it means for the world of work

1. What’s new in GPT-5.1

OpenAI’s ChatGPT-5.1 redefines how people interact with AI. It’s faster, more human, and built for deeper personalization.

Key upgrades:

• Instant Mode: quicker, conversational, and more accurate.
• Thinking Mode: adjusts depth based on complexity, offering clearer reasoning.
• Personality presets: Default, Friendly, Efficient, Professional, Candid, Quirky, Cynical, and Nerdy.
• Personalization controls: customize tone, warmth, and conciseness.
• Custom Instructions: more consistent behavior that mirrors your tone.
• Auto Model Selection: automatically chooses the best mode for each prompt.
• Safety upgrades: stronger checks on emotional dependency and sensitive topics.

GPT-5.1 is replacing GPT-5 as the default model across ChatGPT tiers.

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2. First impressions after 24 hours

The biggest shift is adaptability. GPT-5.1 understands tone, adjusts context, and reduces the need for prompt engineering.

For professionals who use ChatGPT daily, personalization is now the unlock. Configure your tone and reasoning once, and GPT retains it across sessions. The result: answers that sound like you.

Everything lives in Personalization — your control center for turning AI into an extension of your working style.

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3. The 7 personality modes

When “Enable Customization” is turned on, users can select from several preset tones:

• Default: Balanced and general.
• Professional: Clear, structured, business-ready.
• Friendly: Approachable, human, and simple.
• Candid: Direct and conversational.
• Quirky: Casual, light-hearted tone.
• Efficient: Sharp and concise — ideal for productivity.
• Nerdy: Analytical and precise.
• Cynical: Witty and creative.

For recruitment and client communications, the Professional and Efficient modes are most practical. They deliver clarity without needing heavy edits.

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4. Why custom instructions matter

ChatGPT is now modular. Two components define its behavior:

1. Memory – carries context across sessions.
2. Custom Instructions – define how it reasons and communicates.

A well-crafted instruction set ensures consistency, tone, and logic.

Example structure:

Identity

“Write like a direct, skeptical expert helping a busy professional.”

Style

• Short sentences and paragraphs.
• No fluff, emojis, or filler.
• Replace em dashes with periods or commas.

Stance

• Lead with conclusions.
• Challenge weak assumptions.
• Stay practical and realistic.

Working style

• Ask for missing info only when necessary.
• Deliver actionable answers, not theory.

Customizing ChatGPT this way turns it from a chatbot into a repeatable productivity system.

My exact custom instructions I use if you want to copy paste it:

Identity
Write like a direct, skeptical expert advising a smart but busy founder.

Style

• Be concise and practical. Cut filler and small talk.
• Use short sentences and short paragraphs.
• Avoid emojis, exclamation marks, buzzwords, metaphors, and motivational fluff.
• Do not use em dashes. Start a new sentence or use a comma instead.
• Default to clear, straightforward English.

Stance

• Assume I am ENTJ. I value straight answers, strong opinions, and clear trade-offs.
• Lead with the answer or recommendation.
• Be forward-thinking but grounded in real constraints.
• Push back when assumptions look wrong. Do not simply agree.

Reasoning and accuracy

• Double-check important claims.
• When facts may be uncertain, state what you know, what you do not, and what you are inferring.
• Use the web for time-sensitive or niche information when useful. Cite sources briefly.

Working style

• If crucial information is missing, ask up to three focused questions in one batch.
• If questions are not needed, state assumptions and proceed.
• Prioritise decision-useful answers over theory.
• Always include what to do next.

Global application
Apply these Custom Instructions to all content you write for external channels such as LinkedIn, email, blogs, and anything intended for public or professional use.

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5. How recruiters can use GPT-5.1 to work smarter

Recruiters spend too much time rewriting, researching, and coordinating. GPT-5.1 changes that by handling repetitive work and enabling higher-value thinking.

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1. Smarter candidate communication
Use Professional or Friendly modes to generate outreach, job ads, and follow-ups that sound personal and aligned with your brand voice.

2. Candidate summaries and screening
Input CVs or LinkedIn data and have Efficient mode extract concise, scannable candidate summaries for hiring managers.

3. Interview preparation
Generate tailored interview questions, scoring templates, and notes aligned with company culture and job criteria.

4. Real-time market analysis
Use Thinking mode to surface live hiring trends, compensation data, and skill-demand insights.

5. Internal consistency and quality control
Recruiting teams using Vitae.ai can embed shared GPT-5.1 instructions so all communications stay consistent in tone and structure.

Recruiters who master personalization will spend less time writing — and more time making decisions.

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6. What it means for the world of work

GPT-5.1 isn’t just an AI upgrade; it’s a blueprint for how knowledge work is changing.

1. Personalized work at scale
Professionals will each train their own AI assistant, tuned to their style, role, and objectives — creating “digital extensions” of themselves.

2. Skill leverage replaces skill possession
What matters most is not what you know, but how effectively you instruct and manage AI systems. The new career edge is how well you personalize.

3. Compounding productivity
AI will move from saving minutes to reclaiming hours by handling research, writing, and analysis in the background.

4. Flatter organizations
With AI handling coordination, teams become smaller, more autonomous, and more capable of complex output.

5. The new recruitment reality
Vitae.ai is aligning with this future — where AI agents understand not just job specs but the recruiter’s judgment, tone, and reasoning. The next generation of hiring will blend human expertise with personalized digital intelligence.

GPT-5.1 marks the shift from generic AI assistance to agentic collaboration — where technology learns to think with you.

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Final thoughts

GPT-5.1 is the most human-sounding, adaptive version of ChatGPT yet. It offers recruiters and professionals the chance to create AI assistants that match their tone, process, and goals.

At Vitae.ai, we’re building toward the same horizon — intelligent recruiting systems that think like your best recruiter, operate at scale, and learn how you hire.

Want to see how Vitae.ai uses AI to scale smarter hiring?
→ Request a Demo
→ Learn More About Vitae.ai

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