Prompt Engineering Evolution Timeline
提示工程演进时间线
Trace the historical development of prompt engineering techniques and tools from 2020 to present, with key milestones and methodologies.
追溯2020年至今提示工程技术与工具的历史发展脉络，梳理关键里程碑与方法论。
Prompt
Trace the evolution of prompt engineering from 2020 to 2025. I want to understand how best practices have changed with GPT-2 → GPT-4 → GPT-4 Turbo, how agents and retrieval-augmented generation have influenced prompt design, and which tools (e.g., LangChain, PromptLayer) shaped the ecosystem. Add timelines, milestones, and voices from the field.