Entropy in LLMs: A Unifying Language from Training to Inference and Products

This article connects cross-entropy, perplexity, temperature, conditional entropy, hallucination detection, and prompt constraints into one line of reasoning, showing how entropy provides a unified language for understanding LLM training, inference, and product design. It also explains entropy’s practical value in RAG and engineering governance.

March 27, 2026 · 6 min · 1263 words · Andy SI
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Spec-Driven Development Explained: From Prompt and Pray to Spec and Steer

This article systematically explains the core concepts and four-stage workflow of Spec-Driven Development, as well as its fundamental difference from vibe coding. Drawing on today’s tools and maturity levels, it explains why writing a specification before implementation substantially reduces ambiguity and rework in the age of AI coding agents.

March 19, 2026 · 12 min · 2443 words · Andy SI
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RAG Chunking Best-Practices Guide

Drawing on benchmarks and industry practice from multiple organizations, this guide presents default RAG chunking settings, parameter-tuning methods, and strategies for different document types.

March 18, 2026 · 10 min · 2050 words · Andy SI
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Agent = Model + Harness

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

March 18, 2026 · 6 min · 1167 words · Andy SI
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The Complete Guide to Concurrency and Parallelism in Python: The Evolution from One Thread to Multiple Cores

Starting with the fundamental distinction between concurrency and parallelism, this guide systematically explains when to use Python’s GIL, threading, multiprocessing, asyncio, and concurrent.futures, how they work together, and how to choose among them.

March 15, 2026 · 18 min · 3774 words · Andy SI
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Python's Async and Iteration Systems: A Complete Review Guide Built Around One Core Metaphor

Using the metaphor of a restaurant kitchen with a single-threaded event loop, this guide systematically explains the complete correspondence among synchronous iteration, generators, coroutines, asynchronous generators, and thread-pool bridging in Python.

March 15, 2026 · 13 min · 2650 words · Andy SI
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The Complete Best-Practices Guide to Prompt Engineering

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.

March 11, 2026 · 19 min · 4045 words · Andy SI
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Notes on Anthropic's Contextual Retrieval

Starting from Anthropic’s Contextual Retrieval article and Appendix II, these notes summarize the core method, experimental findings, and RAG architecture principles suitable for production.

March 11, 2026 · 5 min · 994 words · Andy SI
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Essential Reading for Contextual Retrieval and RAG

A curated list of ten high-value articles on Contextual Retrieval, Context Engineering, and RAG evaluation, spanning Anthropic’s original publications, open-source implementation guides, and a review of 2025 trends.

March 9, 2026 · 4 min · 801 words · Andy SI
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Apple M5 vs. M4: A Practical Comparison for AI Engineers

A practical breakdown for AI engineers of what the M5’s changes over the M4—from CPU, cache, and memory bandwidth to Neural Accelerators—mean for local LLM and diffusion inference.

March 6, 2026 · 13 min · 2757 words · Andy SI
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