Grok is the most permissive of the three: it added an opt-in adult tier (Spicy Mode, August 2025) and generates sensitive content ChatGPT and Gemini refuse outright, but moderates reactively — tightening image rules on January 9, 2026 after deepfake backlash. ChatGPT enforces strict published refusal categories; Gemini prohibits by design with no user override.
The clearest way to compare the three is by moderation posture: Grok is permissive and incident-driven, ChatGPT is restrictive with a stable published framework, and Gemini is restrictive by architectural design.
Grok — opt-in permissiveness, reactive enforcement. Grok launched an opt-in adult content tier (Spicy Mode) in August 2025 and handles requests the other two reject — in documented AI film production work, Grok generated imagery involving deceased characters and teenagers in distress that both GPT and Gemini refused outright. Its limits move with public pressure: after deepfake backlash, xAI restricted image generation on January 9, 2026, and explicit imagery involving minors stays blocked regardless of mode. Treat Grok's policy as a moving target — a prompt that generates today may be refused after the next incident forces a rule change.
ChatGPT — strict, published, category-based refusals. OpenAI enforces a formal usage policy with explicit prohibited categories — sexual content, violence facilitation, self-harm, anything involving minors — and refuses at the request level rather than adjusting case by case; an announced adult-mode test was paused rather than shipped. In production use it occasionally covers borderline narrative requests, with quality trade-offs: one documented production used GPT as a fallback for depicting a teenage character in distress and found it failed to maintain consistent age appearance across outputs. "Grok behaves like a prodigal son that returns during exceptional cases," as one AI filmmaker put it in documented production notes — the mainstream models handle the routine work, and Grok gets called only when they refuse.
Gemini — safety-by-design with categorical prohibitions. Google builds moderation into the model rather than layering a policy on top: sexual content, hate, harassment, and self-harm content are categorically prohibited with only narrow educational or artistic exceptions, and there is no opt-in tier or user override equivalent to Grok's Spicy Mode. Gemini is the least likely of the three to generate contested imagery; in documented filmmaking workflows it shows up mainly as an analysis tool — scene breakdowns and metadata on finished footage — rather than as a generator for sensitive material.
What to do when a model refuses your request. Use Grok as the exception-case model for legitimately sensitive narrative imagery rather than as a default, since its permissiveness comes bundled with policy volatility. When even permissive models flag a frame, render the image in sepia tone with low detail — a documented workaround that passes content filters while preserving narrative intent. Also note that these policies govern chat assistants, not your full pipeline: video generation models like Seedance 2.0, Kling, and Veo run under their own separate moderation rules, and the invideo agent routes each shot to whichever model fits the content and style your film needs.
Watch some of these to see what works for you:
Grok behaves like a prodigal son that returns during exceptional cases.
— an AI filmmaker, in documented production notes on model selection