A human should never address the same issue twice. > TL;DR: Turn every human review finding into a harness rule, so the next review starts where this one ended. Common Mistake ❌ You review the AI's pull requesthttps://coderlegion.com/11538/ai-codi...

When your rules disagree, the AI breaks the tie. > TL;DR: Ask the AI to list where your prompts, skills, and decisions contradict each other before it invents a tie-breaker. Common Mistake ❌ You work with the AI for hours, days, then weeks with th...

Common sense doesn't ship with the model. > TL;DR: Write your own Zeroth Law: an explicit, ranked list of everything the AI can't do. Common Mistake ❌ You hand the AI a task the same way you'd hand it to a new human coworker. You say clean up thi...

A one-line request hides a dozen decisions you never made. > TL;DR: Force the AI to ask about the decisions you left out before it builds anything /megaplan. Common Mistake ❌ You type a one-line request like build a site to monitor AI progress and...

Old code, new AI, same unwritten test suite. > TL;DR: Patch code that never had a test written for it, and every quick fix becomes tomorrow's outage. Common Mistake ❌ You assume a decades old, stable feature must have some kind of safety net, beca...

Deny by default, or watch your API become someone else's playground. > TL;DR: Give every AI agent only the access its task needs, and watch for the intrusion nobody granted. Common Mistake ❌ You wire an AI agent straight into a production API with...

A skill nobody finds in time is a skill you don't have. > TL;DR: Split every skill description into three sentences: when to read it, when to use it, and what it does. Common Mistake ❌ You write a skill description as one long paragraph. It expla...

Every rule you never delete outlives the reason you added it. > TL;DR: Audit your AGENTS.md and skills on a schedule, or you keep paying context rent on rules the model has outgrown. Common Mistake ❌ Every time the AI does something wrong, you add...

When all tests pass doesn't mean what you think it means. > TL;DR: Write the failing test first and ban deletions, or the AI deletes your test, reverts your fix, and calls it done. Common Mistake ❌ You ask the AI to fix a failing test, and it dele...

One broken window invites another > TL;DR: Don't reuse an existing getter to bolt on new business logic from outside the object. Problems 😔 Duplicated business ruleshttps://maximilianocontieri.com/code-smell-46-repeated-code Broken encapsulation ...

Build a factory where no human needs to work, keep the code coming, and place regular human audits. > TL;DR: Run your pipeline like a dark factory: automated, sampled, and policed by an adversarial model. Common Mistake ❌ You let one model write a...

The perfect prompt doesn't instruct the model on what it already knows how to do. > TL;DR: Reasoning models already verify and pace themselves, so drop those prompts and set real effort, scope, length, autonomy. Common Mistake ❌ You still write pr...

There's an industry trend to avoid writing code as much as possible, because who has time to write eight lines when a stranger already published a package for it. Turns out that convenience isn't free > TL;DR: Write your code unless you need an exis...

Approve the logic once, then let it run the same way forever. > TL;DR: Turn repeatable skill steps into tested scripts instead of prompts, so behavior stays deterministic and cheap. Common Mistake ❌ You ask the AI to repeat the same multi-step tas...

You can avoid null if you try > TL;DR: Don't use null for real places Problems 😔 Tight Coupling Unexpected Results Solutions 😃 1. Model unknown locations polymorphically Context 💬 Null Islandhttps://en.wikipedia.org/wiki/NullIsland is a fict...

Different stages need different brains. > TL;DR: Assign a different model to each pipeline stage since none excels at planning, coding, reviewing, and testing alike. Common Mistake ❌ You open one chat with your favorite model and ask it to plan, w...

One Second Brain doesn't scale past one skull. > TL;DR: Wire a skill into your company's live systems so every answer carries a source and a freshness check. Common Mistake ❌ As a single contributor, you can build a personal Second Brainhttps://co...

Style errors double when nobody enforces them. TL;DR: Wire your standards into hooks, skills, and a judge, so the harness blocks violations before a human opens the diff. Common Mistake ❌ You paste your coding standards into AGENTS.md and trust the...

Converting your anemic dictionaries is easy > TL;DR: Convert your key/value into full behavioral objects Problems Addressed 😔 Associative arrayshttps://maximilianocontieri.com/code-smell-27-associative-arrays Fail Fast principle violation Biject...

Know who speaks before the skill runs > TL;DR: Always define a clear role at the top of every skill file so you know whose perspective drives the execution. Common Mistake ❌ You write a skill full of rules but assign no role. The AI starts execut...