19 AI coding rules, all from 14 of my posts that 𝗲𝗮𝗰𝗵 𝗽𝗮𝘀𝘀𝗲𝗱 𝟮𝟬𝟬𝗞 𝘃𝗶𝗲𝘄𝘀. Together those posts have 8.7M+ views and 94K bookmarks.
Last night I went back through six months of posts, broke them down rule by rule, rewrote each one, and took several drafts to get to the list below.
Kickoff
1. When you hand it a task, give it a goal: how far to take it, how to verify each step, and what counts as done.
2. When unsure, ask first. Don't silently pick one interpretation and run with it. Touch only what's required, and don't fix up neighboring code on the way.
3. For any task over 5 steps or 30 minutes, have it build a progress dashboard before it starts and update it after every step: progress, what's stuck, questions waiting on you, and what it'll do by default if you haven't answered. In Claude Code, make it an artifact: the page refreshes in place, and Ctrl+] opens it anytime. In other tools, a local HTML page works.
In AGENTS.md / CLAUDE.md
4. Delete lines like "think carefully" and "take a deep breath" that push it to think more. Opus 5.5 already thinks before every reply and decides how much. Delete them and 𝗿𝗲𝗽𝗹𝗶𝗲𝘀 𝗰𝗼𝗺𝗲 𝗯𝗮𝗰𝗸 𝗳𝗮𝘀𝘁𝗲𝗿, with no drop in quality.
5. If code is only used in one place, don't pull it out into an abstraction, adapter or config layer. Add one when a second place actually needs it.
6. Don't design for rare or future cases nobody asked about. Delete the old code you replace, unless compatibility is an explicit requirement.
7. Before adding a dependency, changing a public API or data format, or deleting user data, stop and ask me.
8. When you switch models, have the new one review your AGENTS.md and skills against the official guide: overly broad triggers, docs it has to read for every task, redundant checks, conflicting instructions, and rules that make it stop and check with you before the work is done. Recommendations first, no edits yet.
UI
9. Give it a DESIGN.md first that spells out colors, type sizes, spacing, corner radius, shadows and component rules, and have it read the file before every UI build. Don't want to write one? Take a ready-made DESIGN.md from a product you like and drop it in your project root.
10. Codex has image generation built in. If you think the UI it made is ugly, tell it: "Use imagegen to reimagine this page, then implement it."
11. Pick one page and have it redo it in the style of a product you like. Pin down the style first: a restrained palette, a clear type hierarchy, plenty of whitespace. Visuals only, no new features, and have it walk you through every change.
12. Cut taglines, helper text and secondary labels. If a screen needs them to make sense, fix the layout.
When you're stuck
13. When fixing a bug, have it find the root cause and explain the fix before it touches the code.
14. If Opus 5.5 is your main model, run /advisor fable to put Fable on the sidelines as an advisor. Before committing to a plan, when the same error shows up a second time, and before saying it's done, Opus checks with it first. Opus still writes the code.
Before you ship
15. Have Opus 5.5 send out 5 subagents to check the 20 things worth checking (design, mobile, plus the loading, empty and error states), then fix them all in one pass.
16. Then send 4 subagents after the 20 things that slow a site down. Run Lighthouse in mobile mode three times before and after the fixes and compare the medians. Don't cut features to gain speed.
17. Last, have it play the bad guy: with two regular user accounts and one admin account, actually run all 14 attacks, keep the evidence, then fix what it finds.
Saving usage
18. Start effort at medium: low for mechanical edits, medium for everyday work, high when medium gets stuck, and save xhigh and max for work where you've measured a gain.
19. Subagents that only search, read logs or run tests need their own model, or they all run on your main model. Unused MCP servers and a CLAUDE.md well over 200 lines 𝗲𝗮𝘁 𝘂𝘀𝗮𝗴𝗲 𝗲𝘃𝗲𝗿𝘆 𝘁𝘂𝗿𝗻. Turn those MCPs off and cut CLAUDE.md down.
Each rule's original post is linked in the first reply. The full checklists and prompts are in those posts.
