Prompt design that survives a model upgrade, schema-constrained output, few-shot choices, and getting parseable results without a retry loop.
3 questions in Generative AI & Large Language Models.
Constrain the decoder to a schema instead of asking for JSON in prose, reserve enough output tokens that a complete document fits, validate at the boundary, and allow one repair retry that quotes the exact violation back.
Pin the model version, keep the prompt to stable intent and a schema, and record every model-specific workaround as dated, deletable debt. The durable artefacts are the output schema and the eval set - they are what tells you whether the new model is better before you ship it.
The system prompt holds what is identical on every request - role, policy, output contract, tool schemas, examples. Anything varying by user or request, retrieved documents included, belongs in the turns below, to keep the cached prefix stable and untrusted text away from system authority.