If you are not a developer and you just started using Claude Code, you have probably hit at least one of these:
- It says "I've updated all 40 files!" and 12 were actually changed.
- You asked for one typo fix and it rewrote the whole paragraph.
- It tried the same broken fix four times in a row.
- A file you cared about is gone.
None of this means the tool is bad. It means it has no rules yet. Below is the setup I would give any non-coder on day one: one short rules file, one permission check, and one habit. It takes about 15 minutes.
1. Create a rules file (CLAUDE.md)
Claude Code reads a file called CLAUDE.md at the start of every session in that folder. Think of it as the note you would leave a new assistant on their first day.
The easiest way to start: open Claude Code in your project folder and type /init. It drafts a CLAUDE.md for you. Then add the block below.
Keep the file short. Anthropic's guidance is to stay under roughly 200 lines, and specific rules are followed far more reliably than vague ones. "Be careful with files" does nothing. "Never edit files in final/" works.
2. The five-line safety block
If you add nothing else, add this:
- Change only what I asked for. Mention other ideas at the end; do not act on them.
- Never delete, overwrite, send, publish, or spend money without my explicit yes in this conversation.
- For changes to more than 3 files, show a numbered plan first and wait.
- Never say "done" until you have checked the saved result. Show the evidence.
- If the same approach fails twice, stop and explain the cause before trying again.
Each line maps to one of the failures above. Line 4 is the one that matters most. Finishing the steps feels like finishing the task, so unless you ask, it may never reopen the result.
When it still says "done" too early, type this:
Before we continue: open every file you said you changed and confirm the change is actually there. Give me a table: file, expected change, found yes/no.
3. Check your permission mode before every big task
Press Shift + Tab to cycle permission modes. The current mode shows at the bottom of the screen.
| Mode | What happens | Use it when |
|---|---|---|
| Manual | Asks before editing files or running commands | Your first week, and anything you care about |
| Plan | Reads and plans, edits nothing until you approve | Before any big change |
| Accept edits | Edits files without asking | Working on copies, reviewing after |
| Auto | Acts without asking, with background safety checks | Only once you trust your setup and have a backup |
On recent versions, new sessions may start in Auto by default. Look at the bottom of the screen at the start of each session. If you want Manual every time, ask Claude Code: "Set my user settings so new sessions start in manual permission mode. Show me the exact change before saving it."
Rules in CLAUDE.md are guidance. For things that must never happen, use /permissions. For example, an ask rule like Bash(rm *) makes it prompt you before any delete command, in every mode.
4. Keep your own backup, because /rewind has limits
Claude Code takes automatic checkpoints, and /rewind (or pressing Esc twice) restores them. But checkpoints only cover edits made with its own file-editing tools. Files moved, copied, or deleted through terminal commands are not covered.
So before any task that touches many files, make a copy of the folder. If you are comfortable with it, a git save point works too. Either way, it takes 30 seconds and it is the difference between an annoying afternoon and a lost one.
5. When it forgets or loops: /clear, not "try again"
Long sessions fill up the context, and quality drops. If it starts forgetting earlier instructions or repeating the same fix:
- Ask it to write a 10-line summary of where things stand into a file.
- Type
/clear. - Start fresh: "Read summary.md and continue from step 3."
Type /context any time to see what is loaded, including whether your CLAUDE.md is actually being read. If a rule keeps being ignored, that is the first thing to check.
That is the whole day-one setup: a rules file, the safety block, a permission check, a backup habit, and knowing when to clear.
I packaged the longer version as a kit for non-coders: a full day-one checklist, 4 ready rules files (solo business, content creator, operations/admin, small online store), 20 copy-paste work orders, and a guide to the 10 most common ways it redoes or breaks your work. There is a free sample too: https://plainterminal.gumroad.com/l/gasszg
Not affiliated with Anthropic. Commands checked against the official Claude Code docs in September 2026. Written with AI help and reviewed.
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