Five Things I’d Decide Before Paying for Claude Code

I have not started using Claude Code yet.
That is exactly why I wanted to write this down first.

After seeing an X post about “the first five settings to make after installing Claude Code,” I realized my question is slightly different: if I were going to pay a meaningful monthly cost for it, what should I design before I start?

My current takeaway from Anthropic’s documentation is simple:

CLAUDE.md is for persistent instructions and working rules
settings.json is for permissions and safety controls

That distinction matters.
I do not want to rely on a long instruction file for everything, especially when some things should be enforced by permissions instead of politely requested in prose.

The five things I would define first

1. Working rules

I would define how the tool should work before I define what it should produce.

2. Output language

I would lock the default response language and explanation level early, especially for non-technical writing and documentation work.

3. Confirmation level

I would decide which tasks can proceed automatically, which need a short heads-up, and which must always stop for approval.

4. Allowed and blocked areas

I would describe the project structure in CLAUDE.md, but block sensitive files such as .env and secrets/ through permissions.deny in settings.json.

5. Definition of done

I would decide what “finished” means before using the tool in real work.

Draft examples

Minimal `CLAUDE.md`

# Working Rules

- Respond in Japanese by default
- Explain technical terms briefly
- Summarize the goal before making changes
- Ask before large edits, deletions, or publishing actions
- Treat `posts/` as published content, `content/drafts/` as drafts, and `docs/` as rules
- Do not expand scope without being asked

Minimal `settings.json`

{
  "permissions": {
    "deny": [
      "Read(./.env)",
      "Read(./.env.*)",
      "Read(./secrets/**)"
    ]
  }
}

My current view

Before using Claude Code, I would rather define its way of working than rush into usage.
If this tool becomes part of daily work, the gap after three months will probably come less from raw model quality and more from how well the rules were designed at the start.