It could be useful for downstream/AI processes. Eg hand-written code only requires 70% code coverage because the cost for higher coverage is significantly higher, while AI generated code requires 90% coverage because the cost of getting coverage is lower.

Especially if the prompt is attached to the metadata. Then reviewers could note how you could have changed the prompt or potentially point an AI at the bug and ask it to add something to AGENTS.md to prevent that in the future.