ContextEngineering

A systematic guide to lexical retrieval, dense retrieval, hybrid fusion, reranking, evaluation, observability, and production governance in RAG systems.

Drawing on Latent Space’s interview with Shunyu Yao, this article reviews ReAct, Reflexion, Tree of Thoughts, memory, benchmarks, ACI, and Agent UX, and summarizes the importance of tools, environments, evaluation, and interface design when putting AI agents into practice.

Starting from the trend of platforms absorbing basic RAG pipelines, this article examines the high-premium skills AI application engineers should prioritize in 2026: evaluation and observability, data governance and access control, and deep engineering capabilities for agentic workflows.

This article presents a core design framework for excellent AI agent systems, covering Spec-Driven Development, a three-layer architecture, resolvers, the boundary between latent and deterministic work, diarization, and a self-improving learning loop, helping engineers move from autocomplete-tool thinking to AI-augmented software engineering.

Drawing on 2025–2026 practices in AI coding agents and Spec-Driven Development, this article systematically explains the definition, value, essential components, workflow, and common pitfalls of a Software Spec, and provides a practical template for tools such as Claude Code, Codex CLI, and Cursor.

Starting from how AI coding agents execute work, this article explains why agent-native documentation has evolved from reference material into infrastructure, defines the responsibilities and organization of AGENTS.md, PRD, Architecture, Spec, and Plan documents, and shows how Context Engineering and Spec-Driven Development can produce a context-efficient system that reliably directs agent behavior.

This article systematically reviews frontline experience from OpenAI, Anthropic, HumanLayer, and other teams documenting AI coding-agent projects. It explains why entry-point files, layered knowledge bases, state-tracking files, and local documentation directly affect Agent performance, and provides an actionable path from a minimum viable documentation system to continuous maintenance.

Begin with a Comparison You ask ChatGPT, “What is a KV cache?” The model answers, and the conversation ends. You tell Codex CLI, “Add a user-authentication module to this project, including tests.” The agent begins working autonomously: read the project structure → understand the existing code → plan the implementation → write authentication logic → write tests → run tests → observe a failure → fix it → get the tests passing → open a pull request. The process may span dozens of steps without requiring your intervention. The underlying LLM may be the same, but the behavior is entirely different. The first is the traditional use of an LLM. The second is an agentic use. This article explains the nature of that transition. It is more than a stronger model. It is a fundamental shift in the way the model is used, and that shift reshapes the entire engineering system around it. ...

LangChain’s breakdown of the agent harness connects context engineering, memory, MCP, and the agent loop into one coherent map.

A long-form Prompt Engineering guide for AI application engineers, covering foundational principles, context design, task chains, injection defenses, agent prompt design, and evaluation-driven development.