Gemini and ChatGPT don’t remember your character between images. Every prompt starts from zero — hair color shifts, the face changes, the outfit from panel three doesn’t match panel four. Put that character in a forest, then a hallway, then a rooftop at night, and each scene resets unless something tells the model otherwise.

CastLock extracts a character once — from a reference image and the handful of details that can’t vary — and compiles it into one locked prompt. Reuse that same prompt in Gemini or ChatGPT for every scene, and the character in scene ten still looks like the one you started with.

You copy the prompt yourself and paste it into the AI tool you already use. No API keys, no automation, no data leaving your Mac. $50, once. No subscription, no tiers, no upsell screen down the road.