How to Build a Text Prompt Moderation Gate for AI Image Generation in Node.js

Developers building AI image generation platforms must moderate all user-controlled text fields — including prompt, style, and negativePrompt — before triggering image creation. A chat completion classifier returns a strict JSON object with one of three decisions: allow, review, or block, which then determines the application's next step. Using a schema-enforced response prevents ambiguous output and converts probabilistic model judgments into deterministic code branches. The review state is intentionally preserved to handle borderline cases without forcing uncertain prompts into outright approval or rejection. The implementation uses Node.js with native fetch and environment-configured model IDs, keeping the solution free of client library dependencies and tightly coupled provider logic.