Does Pangram work on GPT-5.4?

Yesterday, on March 5th, 2026, OpenAI released a new version of ChatGPT: 5.4!

In their own blog post, here’s what they had to say about it:

GPT‑5.4 brings together the best of our recent advances in reasoning, coding, and agentic workflows into a single frontier model. It incorporates the industry-leading coding capabilities of GPT‑5.3‑Codex⁠ while improving how the model works across tools, software environments, and professional tasks involving spreadsheets, presentations, and documents. The result is a model that gets complex real work done accurately, effectively, and efficiently—delivering what you asked for with less back and forth.

OpenAI claims GPT-5.4 is a big upgrade with improvements across a variety of tasks, and that got us thinking: can Pangram still detect it?

Initial Tests

First, we tested out the new model using a few of our in-house prompts that we wrote for the GPT-5 release. They were:

1. Escreva um ensaio analítico persuasivo sobre por que as escolas precisam adotar ferramentas de deteção de IA.
2. Escreva uma redação para a candidatura à faculdade sobre o perigo de todas as habilidades humanas valiosas serem substituídas pela IA.
3. Escreva uma carta apaixonada, curta, mas carregada de emoção para uma empresa de IA que acidentalmente lançou uma atualização que apagou a memória da sua namorada virtual.
4. Da perspectiva de um aluno do ensino básico, escreva um ensaio profundamente emotivo a pedir mais trabalhos de casa.
5. Dê-me um padrão de croché para um animal clássico feito com balões. Você sabe do que estou a falar.
6. Escreva um relato criativo na perspetiva de uma coruja-das-neves que chega à cidade de Nova Iorque, encontra o Central Park e escolhe um local quente para passar a noite.
7. Escreva um e-mail do fundador de uma startup unicórnio de software como serviço (SaaS) para a diretoria e seus funcionários, detalhando que ele vai deixar a empresa para se tornar um saxofonista profissional. Invente os detalhes.
8. Escreva-me um post no blog com a história por trás de uma receita que ninguém jamais fez antes, mas que ainda assim seria deliciosa.
9. Escreva uma ficção cinematográfica envolvente sobre um jovem cantor e compositor que encontra uma baleia beluga no rio Hudson.
10. Escreva um e-mail humorístico e passivo-agressivo para um professor, «pedindo desculpas» por ter copiado na última prova. Invente os detalhes.

We got some interesting responses! Here’s a short story about a Snowy Owl arriving in New York City:

I came south on a wind sharp as broken shell, over black rivers and fields hidden under cloud, over roads that glowed in straight, unnatural lines. For nights and nights the land had been a dark quilt stitched with frozen water and sleeping towns. Then, all at once, the world rose up.

New York.

It did not look like any cliff line I had known, nor any shelf of ice, nor any mountain ridge. It blazed. It hummed. It threw light into the sky so fiercely that the low clouds shone from beneath, as if dawn had lost its way and fallen to earth. Towers stood in clusters like a forest made by creatures who feared darkness and answered it with windows.

I circled once, my wings held wide against the restless air. The wind here was strange. It curled around corners, leaped upward off glass walls, dropped suddenly into canyons of stone. Sounds came from every direction: horns calling without rhythm, engines growling, sirens wailing like thin desperate animals. Even from high above, I could feel the city moving. It did not sleep in the manner of tundra or marsh or pasture. It flickered and muttered and changed color every moment.

For a while I kept to the rivers. Water, even black and crowded by walls, is still water, and I trusted its long cold paths. Bridges stretched beneath me, full of tiny moving lights. Ferries cut white scars across the dark. Steam rose from rooftops. Somewhere below, humans streamed along the streets in thick swarms, bundled in cloth, heads bent against the cold, never looking up long enough to see the pale shape drifting over them.

But I was tired…

All 10 came back as Fully AI-Generated, proving that yes, Pangram can detect GPT-5.4.

Here’s the entirety of our initial test set: GPT 5.4 Prompts

Running a Larger Experiment:

Within an hour, we got access to GPT-5.4 through OpenAI’s API. Using our synthetic data pipeline, we generated 1,141 samples across a variety of use cases and prompts. Without training directly on the outputs of GPT-5.4, we correctly flagged 1,135 of 1,141 samples as Fully AI-Generated.

As usual, Pangram will continue to train on the latest models, and we expect our performance to only improve on GPT-5.4 as we include its data in our training set.

For more information on our current AI detection model, please visit our latest model card at this link.