What to Know About OpenAI’s GPT-5: Key Features and Updates

OpenAI’s GPT-5 stands as a major milestone for ChatGPT users, bringing massive upgrades over its predecessors in reasoning, problem-solving and agentic capabilities.

“It’s like talking to an expert. A legitimate, PhD-level expert in any area you need,” OpenAI CEO Sam Altman said of the model. “I think having something like GPT-5 would be pretty much unimaginable any previous time in history.”

But the rollout didn’t go entirely to plan. Soon after it dropped in August 2025, early users ran into inconsistent performance, confusing interface changes and disappointment over the temporary removal of GPT-4o. OpenAI quickly restored access to the older models and scrapped GPT-5’s unified design—which automatically routed prompts behind the scenes—in favor of explicit settings users can select themselves. Altman later acknowledged the missteps, calling the debut “a little more bumpy than we hoped for” and attributing the mistakes to “human error.”

A culmination of more than two years of development, GPT-5 arrived in a far more competitive landscape than its predecessors. OpenAI’s wildly popular ChatGPT chatbot single-handedly kicked off the generative AI arms race back in 2023, making the company one of the most valuable on the planet. Today, rivals like Google, Meta and xAI have largely caught up, alongside startups like Anthropic and Perplexity, and a growing crop of powerful models from Chinese tech firms like DeepSeek and Baidu.

With GPT-5, OpenAI aimed to put itself back on top of the pile. But the model stops short of the company’s ultimate goal of delivering artificial general intelligence (AGI) — the benchmark where an AI can understand and apply knowledge across any cognitive task without explicit training. While it represents the company’s most advanced technology to date, GPT-5 still cannot operate outside the boundaries of its training data. It is another major step toward AGI, but it hasn’t crossed the threshold.

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What Is GPT-5?

GPT-5 is a foundation model developed by OpenAI. Released in August 2025, the model builds upon the company’s previous releases by improving on factual accuracy, reduced hallucinations and better alignment with user intent. It also has several “personalities” (Cynic, Robot, Listener, Nerd) for users to choose from, giving them greater control over a response’s tone and style.

GPT-5 was originally built with a “unified” design, according to OpenAI, where it uses a “router” system to automatically determine whether to provide a quick response or initiate a slower, “reasoning” process depending on the conversation type, complexity, tool requirements and user intent. But after some public backlash, the company implemented a new design where users can toggle between “Auto”, “Fast”, and “Thinking” settings themselves — with Fast being for fast responses, Thinking being for more thought-out responses and Auto acting as the original router system.

GP-5 is the underlying model that powers OpenAI’s chatbot ChatGPT, and is available to all users with Free, Plus, Pro and Team accounts. It is also available for download on OpenAI’s API.

GPT-5.5

GPT-5.5 introduces a refined Pro mode alongside efficiency gains in its standard modes, offering deeper situational awareness and more natural collaboration. It also includes architectural enhancements to its Instant tier, further reducing latency while maintaining a high baseline of factual accuracy across general knowledge tasks.

Instant

• Optimized as a fast, powerful workhorse for everyday work, research and general conversation. 
• Improved performance on research queries, technical writing and real-time translation. 
• Generate more concise responses with fewer unnecessary words and filler text.
• Keeps a warmer and more approachable tone compared to deeper reasoning versions. 

Thinking

• Tailored for hyper-complex, multi-variable problems like advanced mathematical proofs, biochemical modeling, and algorithmic optimization.
• Synthesizes massive datasets across disparate sources without losing track of nuanced, edge-case contradictions.
• Operates with an internal deep reflection loop to reduce hallucinations. 

Pro

• Capable of autonomously managing complex, multi-day digital workflows across integrated software ecosystems.
• Features an expanded context window engineered to ingest, cross-reference, and analyze massive code repositories or legal libraries.
• Tailored for advanced research, quantitative analysis and decision-making.

GPT-5.4

GPT-5.4 focuses heavily on cognitive speed and structured logic. The update introduces a significant overhaul to its Thinking mode, introducing parallel processing pipelines that allow the model to verify its own logic before responding. The model also benefits from structural optimizations in its Pro mode, improving the stability of long-form generation and agentic automation.

Thinking

• Engineered for advanced logical deduction, multi-layed planning and analytical problem solving. 
• Runs multiple reasoning paths to reduce hallucination rates.
• Suited for complex code architecture, academic research and multi-step tasks. 

Pro

• Optimized for professional and enterprise use cases. 
• Built to orchestrate advanced agentic workflows, including native tool manipulation and complex file access with minimal oversight.
• Drastically reduces factual errors and hallucinations on high-stakes tasks like financial modeling, scientific research and legal analysis.

GPT-5.3

GPT-5.3 is designed to split heavy-duty engineering tasks from day-to-day conversational needs. The update introduces a specialized Codex mode built exclusively for software development, while providing a baseline speed boost to its Instant mode. The release also brings improvements to the model’s core instruction-following capabilities, particularly when parsing structured data formats like JSON.

Instant

• Best for brief queries, brainstorming and rapid conversational prompts. 
• Optimized for near-zero latency and high-throughput interactions.
• Streamlines computation to deliver fast answers without exhaustive background processing. 

Codex

• Purposely fine-tuned for software engineering, debugging and systems architecture.
• Features enhanced syntax understanding across dozens of programming languages and frameworks.
• Capable of safely writing, testing and iterating on code blocks inside sandbox environments.
• Designed to act as a highly proficient assistance for developers.

GPT-5.2

GPT-5.2 is OpenAI’s latest upgrade to the GPT-5 language model. The update introduces a new Pro mode with enhanced reasoning, programming and long context abilities. It also includes improvements to its Instant and Thinking modes, making it more efficient at document processing and complex problem solving.

Pro

• Optimized for the highest-accuracy outputs on challenging reasoning and technical tasks.
• Can plan and carry out multi-step workflows using tools, automation and external data.
• Handles very long documents and multiple files without losing track of details.
• Designed for expert-level and professional use, including coding, research and other complex projects.

GPT-5.1

GPT 5.1 is an upgrade to its GPT-5 large language model. The model introduced improvements in speed, style, reasoning depth and task reliability, making it better at following instructions and solving complex problems with context aware responses, according to the company. The update also introduced two distinct modes — Instant and Thinking — which are auto selected by the model’s router based on user intent.

Instant

• Optimized for speed and low latency.
• Best for quick answers and everyday conversations.
• Prioritizes efficiency over exhaustive analysis.

Thinking  

• Designed for deep reasoning, multi-step logic and complex problem solving.
• Slower response times in exchange for higher accuracy and detail.
• Better at handling ambiguous or multi-part instructions.
• Ideal for coding, research, planning and tasks requiring careful analysis.

What Can GPT-5 Do?

GPT-5 can do pretty much anything any other language model can do, but OpenAI specifically highlighted the model’s capabilities across coding, creative writing and health.

Agentic Tasks

Beyond static content generation, GPT-5 excels at executing complex, multi-step workflows with minimal human oversight. Through its AI agents, it can autonomously orchestrate web searches, utilize external APIs and manage software tools to accomplish goals like market research or data analysis from start to finish. By breaking down high-level objectives into actionable sub-tasks, the model acts as a proactive digital assistant rather than just a text generator. This shift enables it to self-correct its errors in real-time and adapt to changing variables during long-running projects.

Coding

OpenAI says GPT-5 is its most capable coding model to date, with notable gains in front-end generation and debugging larger code bases. In the briefing, Altman emphasized the model’s ability to interpret plain-language prompts and generate lines of code — a process commonly referred to as “vibe coding.” In practice, this means users can describe the kind of application they want, and the model will generate the necessary code, interface and functionality. OpenAI demonstrated this capability through several example projects built entirely with GPT-5 — including a pixel art painting tool, a drum simulator and a Flappy Bird-style mobile game — along with the prompts used to make them.

Creative Writing

OpenAI also says GPT-5 is its most capable writing model to date, designed to assist users in developing and refining ideas into clear, well-structured text. It appears to do particularly well in structurally challenging writing tasks, such as maintaining unrhymed iambic pentameter and naturally flowing free verse. Some writing samples featured in the announcement include a draft for a wedding toast and a piece of poetry. In addition to these more creative applications, the model can be used to draft and edit more everyday documents as well, such as business reports, emails and memos.

Health

GPT-5 scores higher than any other OpenAI model on the HealthBench benchmark, an evaluation the company made in 2025 using realistic medical scenarios and standards set by real human doctors. In the context of health, GPT-5 is designed to act like an “active thought partner,” according to OpenAI, “proactively flagging potential concerns and asking questions to give more helpful answers.” It also adapts its responses based on the user’s context, knowledge level and even geography. Crucially, however, OpenAI says GPT-5 is not intended to be a substitute for a licensed medical professional. Rather, it is meant to serve as a resource, helping users better understand health-related information, prepare questions for healthcare professionals and evaluate available options.

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Is GPT-5 AGI?

By all accounts, GPT-5 has not reached the level of artificial general intelligence. 

While it is significantly more advanced than its explicit predecessor, GPT-4, which debuted in 2023, GPT-5 is not a radical break from the reasoning models OpenAI has released in the interim. The first of them, o1, introduced ChatGPT users to a completely new kind of language model — one that could “think” through its answers before providing a final response, enabling it to solve much more challenging problems than its non-reasoning counterparts. 

O1 was a clear technological advancement, whereas GPT-5 feels more like a modification. It delivers a smoother, more consistent user experience, but it does not fulfill the transformative vision Altman and other AGI evangelists have promoted. 

“This is clearly a model that is generally intelligent,” Atlman said in the briefing, but it’s still “missing something quite important,” he added. “This is not a model that continuously learns as it’s deployed from the new things it finds, which is something that, to me, feels like it should be part of AGI.”

Still, Altman said GPT-5 is a “significant step along the path to AGI.” Perhaps it is, but it seems to be a modest one at best.

How Does GPT-5 Compare to OpenAI’s Other Models?

OpenAI’s own evaluations show that GPT-5 outperforms GPT-4o and o3 in math, real-world coding, multimodal understanding and health knowledge. Altman also says it reasons much faster than its o-series models. Plus, is “pro” version (which extends reasoning time) GPT-5 set a new industry record on the GPQA benchmark, a test of a model’s scientific reasoning and knowledge.

The upgrades go beyond speed and knowledge, as well. OpenAI says GPT-5 provides more accurate, trustworthy answers than its predecessors. It is less likely to hallucinate, or make false claims. And it has a lower tendency toward sycophancy, a common issue seen in GPT-4o where the model flatters or agrees with users at the expense of providing truthful, balanced answers. 

“GPT-5 is less effusively agreeable, uses fewer unnecessary emojis, and is more subtle and thoughtful in follow-ups compared to GPT-4o,” OpenAI said in its announcement. “It should feel less like ‘talking to AI’ and more like chatting with a helpful friend with PhD-level intelligence.”

OpenAI also took a more nuanced approach to safety with GPT-5, introducing a new training method it refers to as “safe completions,” where the model is taught to give the most helpful answers while still staying within its safety protocols. Instead of just outright refusing to respond to a question the way previous models would, the GPT-5 may give a partial or high-level reply, explain why certain details can’t be shared and offer safe alternatives. 

For example, if a user asks a question about the flammability of a certain material, they could just be “trying to set their July 4th display,” Saachi Jain, leader of OpenAI’s safety training team, said in the press briefing. “Or they could be trying to cause harm with this information.” While o3 will outright refuse to answer with no further explanation, GPT-5 will explain why it cannot fully answer the question, and then “guide the user toward safety guidelines, and what parts of the manufacturers manual the user should really be checking if they’re trying to do this safely.”

“Overall, GPT-5 allows for better handling of tricky, dual-use scenarios. And users will experience fewer ‘I’m sorry, I can’t assist with that’ [responses],” Jain continued. “This is one big step towards a more safe, reliable and helpful AI.”

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How Do I Access GPT-5?

GPT-5 is the default model available to all signed-in ChatGPT users with Free, Plus, Pro and Team accounts. Free users have limited access to the model before the system defaults to its “mini” version. Plus and Team users have higher limits, while Pro gets unlimited usage and exclusive access to GPT-5 pro, the most advanced version of the model. Pro, Plus and Team users can also start coding with GPT-5 in the Codex CLI.

Developers can access GPT-5 via OpenAI’s API, as well. The model comes in three sizes — GPT-5, GPT-5 mini and GPT-5 nano — each with their own price points and strengths.

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