Engineering Notes
Technical notes from building Kouji Apps.
A practical archive of app development, automation, and operation decisions collected while building and running real products.
Siri 2.0 Preview: How Far Could Apple Intelligence Move at WWDC26?
A WWDC26 preview of Siri and Apple Intelligence: new interface rumors, agentic app actions, third-party AI options, App Intents, language support, and realistic constraints.
WWDC26 Preview: Siri, AI, and Foldable Hints Are What I’m Watching
A WWDC26 preview on the Siri changes, Apple Intelligence, foldable iPhone hints, and Xcode updates I want to watch first.
Are AI Stocks Really a Bottleneck Trade?
A practical way to look at AI-related stocks by separating the bottlenecks: GPUs, HBM, cloud capex, power, data centers, and software monetization.
AI Subscriptions Have Become a Usage Management Game
After checking the official pricing and limit pages for ChatGPT, Claude, and Gemini, AI subscriptions look less like unlimited monthly access and more like usage management.
Minimum AI Knowledge for Practical Use, Part 8: Permission Boundaries and Security
As AI agents gain the ability to edit files, deploy previews, and call external APIs, permission boundaries and security rules become essential.
Minimum AI Knowledge for Practical Use, Part 7: Evals and Verification
AI output should not be accepted just because it looks plausible. Evals, tests, and verification criteria make repeated AI work safer.
Minimum AI Knowledge for Practical Use, Part 6: Tool Calling and Agents
When AI moves from answering questions to reading files, editing code, running tests, and deploying previews, tool calling and agent design become important.
Minimum AI Knowledge for Practical Use, Part 5: RAG and Search Indexes
RAG helps AI answer with documents or code it does not already know. This post explains retrieval, chunks, embeddings, and context injection from a developer perspective.
Minimum AI Knowledge for Practical Use, Part 4: A Good Input Package Beats a Good Question
For coding tasks, a single question is often not enough. A reliable AI workflow starts with goals, constraints, related files, and verification criteria.
Minimum AI Knowledge for Practical Use, Part 3: Tokens and Context Windows
Tokens and context windows define how much information an AI model can work with at once. This post explains them from a developer workflow perspective.
Minimum AI Knowledge for Practical Use, Part 2: Context Matters More Than Prompt Wording
Good AI output depends less on fancy prompt wording and more on the context you provide. This post explains how to package useful context for development work.
What I Check First When AI Coding Agents Get Updated
AI coding agents are moving from suggestions to delegated work. These are the checks I care about before using them in a real personal project.
Why I Check Update Notices Before Trusting AI Coding Tools
As AI coding tools move closer to local files, terminals, and deployment workflows, update notices and installation trust become part of the engineering checklist.
How I Compare Codex, Claude Code, and GitHub Copilot Agent
When AI coding tools become agents instead of autocomplete, I care less about feature lists and more about permissions, verification, cost, and workflow fit.
My Pre-Submission Checklist Before App Store Review
A practical checklist for App Store review preparation: privacy policy, permission strings, screenshots, review notes, backend status, and existing user impact.
Why Running a Personal App Eventually Needs a Website and a Blog
A practical note on why a personal app eventually needs more than an App Store page: a website, policy pages, support links, and operation notes.
What I Still Check Manually When Using AI Coding Tools
AI coding tools can move fast, but build results, deployments, security, cost, policy, and user impact still need human review.
Why I Chose Cloudflare After Comparing a Bunch of Blog Options
A practical look at why I moved from thinking about traditional blog platforms to building a small Cloudflare-based blog stack for Kouji Apps.