A system prompt is a trade secret only for as long as the model will not repeat it

2026-10-01Trade Secrets

Practice note, Burbage Law, PC, October 1, 2026

System prompts, routing prompts and evaluation rubrics are the most copied assets in an artificial intelligence product and the hardest to protect. Patent protection is rarely available for the text of a prompt, because the words are not a process, and a claim to prompting a model with instructions to achieve a result is the result-oriented claim the Federal Circuit has held abstract since Recentive Analytics, Inc. v. Fox Corp. Copyright protects the exact wording against literal copying and nothing about the technique. That leaves trade secret law, which has one condition that matters here: the owner must have taken reasonable measures to keep the information secret. A system prompt shipped to a model that can be talked into repeating it, or sent to an outside inference provider under terms that permit logging or training, stops meeting that condition the first time someone extracts it, and extraction attempts against any public product are routine.

What it changesRun the prompt library as a trade secret program rather than a code folder: an access-controlled repository, prompt text kept out of client-side code and out of logs, confidentiality and no-training terms in every inference vendor contract, and a documented defense against extraction, because the first question in any misappropriation case is what measures the owner actually took. Where the value sits in the machinery around the prompt rather than in its words, how prompts are selected, assembled, cached or routed, that machinery can be patented, and the application should claim the mechanism and leave the prompt text in the specification as an example at most. A team that cannot say which of its prompts are secrets and which are examples has not made the decision yet, and the decision gets more expensive after the product ships.

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