1Temperature & SamplingHow language models choose their next word, and how temperature and sampling settings turn raw probabilities into practical behavior.Prompting & choice 2Prompting vs RAG vs Fine-TuningThree ways to shape a language model, when to use each, and what tradeoffs they really make.Prompting & choice 3Model SelectionChoosing a model is not a contest for the biggest or newest system; it is a disciplined match between a task, evidence, risk, and cost.Prompting & choice 4Tokens, Cost & LatencyTokens are the unit a model reads and writes, so they explain most of what you pay for and much of how long users wait.Prompting & choice 5Prompting Across ToolsGood prompts travel only when you separate intent from interface, context from commands, and tests from taste.Prompting & choice 6GPT-6 Astra or Claude Opus 5.5 for Building Agents?Why 'which model is best' is the wrong question for agents, and a fair, repeatable way to decide between two frontier models on your own work.Prompting & choice