On Ollama, a model's memory type and its runner decide how much of the cached prompt a new conversation reuses - 8
In freemansoft/Flutter-AdaptiveCards a demonstration Dart chat server asks a local Ollama model for an answer as Adaptive Card JSON. That is a strict, closed-vocabulary schema, which a Flutter app renders as interactive UI. The card system prompt that describes the element vocabulary is about 3,755 tokens. The chat server replays up to ten prior exchanges on every turn. Each Ollama runner keeps a prefix cache, so a request whose opening tokens match an earlier one does not have to process them again. Ollama 0.33.3 and later report, in prompt_eval_cached_count , how many of a reply's prompt tokens came from that cache. A chat server can read from that field how much of each prompt the cache served and where it missed. Every reading below comes from ModelBehavior.md , the lab notebook in that repository. A new conversation reuses a cached system prompt on some models and not on others. The split follows how the model stores its context. A pr...