OpenAI Launches GPT-5.1: Smarter Chats, Easier Personalization

OpenAI released GPT-5.1 with upgrades to Instant and Thinking models, making ChatGPT more conversational, better at following instructions, and smarter at adapting its reasoning time. The update also expands tone customization with new presets and granular controls that apply instantly across all chats. Rollout starts with paid users, adds API support soon, and retains GPT-5 as a legacy option for three months.

Key Points

• Two upgraded models: GPT-5.1 Instant (warmer, more conversational, better instruction following, adaptive reasoning) and GPT-5.1 Thinking (clearer, dynamically adjusts thinking time).
• Adaptive reasoning enables faster responses on simple tasks and deeper reasoning on complex ones, improving math and coding performance.
• Expanded, easier personalization: refined tone presets plus new styles (Professional, Candid, Quirky), with granular tuning for concision, warmth, scannability, and emoji use.
• Personalization updates apply immediately across all chats, and models better honor custom instructions; ChatGPT can proactively suggest tone/style updates.
• Rollout begins with paid users, then broadens; API support arrives shortly; GPT-5 remains available for three months under a legacy dropdown before sunset.

Sentiment

The Hacker News community is predominantly skeptical and critical of GPT-5.1's focus on warmer conversational AI. Technical users overwhelmingly express preference for direct, concise, tool-like interactions and view the sycophantic tendencies as a regression rather than a feature. However, there is a pragmatic minority that acknowledges this direction serves OpenAI's broader consumer market and that the new customization options provide adequate workarounds for power users.

In Agreement

• Some users report GPT-5.1 Thinking is genuinely improved, with better instruction following and less sycophantic output compared to GPT-5
• The personality customization options, particularly the Efficient mode, are acknowledged as a step in the right direction for users who want more control over tone
• The simplified branding from Instant vs Thinking is seen as a welcome improvement over the confusing prior model naming conventions like o1, o3-mini, and 4o
• Several commenters acknowledge that the conversational focus makes sense for OpenAI's core consumer audience, even if it isn't what technical users prefer
• Better adherence to custom instructions is viewed positively by those who rely on system prompts to shape model behavior

Opposed

• The emphasis on warmth and conversational tone is seen as doubling down on sycophancy, which many technical users find counterproductive and trust-eroding
• The conspicuous absence of benchmarks raises suspicion that this is a style-focused release without meaningful capability improvements
• Several commenters argue this direction is a cash grab designed to increase token consumption and push users toward higher-tier subscriptions
• Comparisons with Claude, Gemini, and Kimi K2 suggest OpenAI is losing the technical and coding market while chasing consumer engagement metrics
• Voice mode remains broken with custom instructions not applying and the model adding artificial speech disfluencies like umm
• The model's tendency toward prompt performance, conspicuously narrating its own instruction-following rather than simply executing, is widely criticized
• Concerns about OpenAI potentially using intimate conversational data for targeted advertising and commerce integration