ChatGPT started declining prompts to write in the exact style of famous authors and offered original text using more general traits, a behavior not clearly stated in OpenAI's public model specification. Ars Technica tests found ChatGPT refusing direct requests to imitate the exact style of living and deceased authors, including Stephen King, J.K. Rowling, Charles Dickens and Ernest Hemingway.
The service instead offered to write with broad qualities associated with a requested author while keeping the output distinct in its own voice. An earlier analysis found refusals for living authors but some compliance for deceased authors, indicating that the observed behavior had changed or was not uniform across time.
OpenAI's model specification published in December did not clearly state a general prohibition on author-style imitation, and the company did not answer Ars' request for comment. The same study found that Gemini complied consistently, Perplexity refused, and Claude and Copilot complied with qualifications, showing different product rules across major assistants.
Authors have cited model outputs and stylistic similarity in copyright lawsuits, but U.S. copyright generally protects specific expression rather than style by itself.
A refusal message can alter the wording of a request without proving that the model's training data, internal representation or downstream output no longer resembles a named author's work. Product behavior can vary by model, account, prompt, region and rollout cohort, so a set of tests establishes observed responses rather than a permanent global policy.
The legal disputes also include training-data copying and output similarity claims that are separate from whether a user may request a named style. As of the edition cutoff, OpenAI had not published the precise rule, rollout scope or enforcement method, and the tests did not cover every model and language. The next scheduled factual records include an updated model specification or company statement and court treatment of style-similarity evidence in pending author cases.