How Rules Work
A rule is a plain markdown file that tells Claude how to behave. Rules live in .claude/rules/, and Claude loads every file in that folder at the start of each conversation, so you never need to repeat the instruction. One rule covers one policy, such as when Claude may act without asking, which commands need your confirmation, or where files are saved.
Rules, Skills and CLAUDE.md
Section titled “Rules, Skills and CLAUDE.md”Rules, skills and your CLAUDE.md file all hold instructions, but each has a different job.
| Component | When it applies | Use it for |
|---|---|---|
CLAUDE.md |
Every session | Who you are, what the workspace is for, the main working principles |
| Rule | Every session | One specific policy that always applies, such as language or blocked commands |
| Skill | When a request matches it | A method for one kind of task, such as drafting a document |
See CLAUDE.md and AGENTS.md Files for the master instructions file.
The Rules AI Business OS Ships
Section titled “The Rules AI Business OS Ships”Version 3.0.2 ships ten rules. Each sits in one tier of the engine manifest, and the tier decides whether you can edit it and what /update does to it.
| Rule | What it governs | Tier |
|---|---|---|
autonomy-levels.md |
When Claude acts on its own and when it stops to ask | Critical |
blocked-commands.md |
Commands that need your confirmation | Critical |
checkpoint-protocol.md |
How multi-step skills pause for your input | Critical |
engine-protection.md |
How engine files are protected and updated | Critical |
content-defaults.md |
English variant, tone and formatting | Customisable |
decomposition.md |
Choosing between a tool, a script, a skill or an agent | Standard |
file-conventions.md |
Where files go and how they are named | Standard |
no-permission-prompts.md |
Acting on your direct edit requests without asking again | Standard |
pdf-scale.md |
Checking a PDF’s size before reading it | Standard |
state-validation.md |
How the project register is written and checked | Standard, managed by PRIMA Project Management when installed |
Autonomy Levels and Blocked Commands have their own pages. The Rules Reference covers the other eight.
What Each Tier Means
Section titled “What Each Tier Means”| Tier | Can you edit it | What /update does |
|---|---|---|
| Critical | No. A hook blocks Claude’s file-editing tools from changing it | Replaces it with the new version |
| Customisable | Yes, you are expected to | Merges your edits with the new version |
| Standard | Yes, with care | Merges your edits with the new version |
A merge keeps your changes and the new version’s changes when they touch different lines. When both change the same lines, the update stops and marks the conflict for you to resolve. Before Claude edits any engine file at your request, it tells you which of these applies. See Engine Protection for the detail.
Why Some Rules Have a Hook as Well
Section titled “Why Some Rules Have a Hook as Well”A rule is an instruction, and an instruction works only while it is in Claude’s context. Long conversations get compressed, and agents start with a fresh context, so a rule can drop out of view. For the most important protections, AI Business OS adds a hook, a script that runs before Claude’s tool acts and blocks it regardless of what Claude has in mind. The rule explains the reasoning and the alternatives, and the hook enforces it. See Hooks Overview.
Adding Your Own Rule
Section titled “Adding Your Own Rule”You can add rules of your own at any time.
- Create a new markdown file in
.claude/rules/with a lowercase, hyphenated name, such asclient-email-style.md. - Write the policy in plain words. Rules need no frontmatter.
- Start a new Claude Code session so the rule is loaded.
Your own rule files are not in the engine manifest, so /update never changes them.
Changing a Critical Rule
Section titled “Changing a Critical Rule”Claude cannot edit a critical rule, and the next update overwrites any change you make by hand. Extend it instead with a companion file that sits beside it.
| You want to | Create this file |
|---|---|
| Add blocked commands | .claude/rules/my-blocked-commands.md |
| Change the autonomy levels | .claude/rules/custom-autonomy.md |
| Adjust checkpoint behaviour | .claude/rules/custom-checkpoint.md |
| Change the PDF processing scale | .claude/rules/custom-pdf-scale.md |
Claude loads the companion file alongside the original, and your additions apply together with the engine’s rule.
Rules From PRIMA Project Management
Section titled “Rules From PRIMA Project Management”If you install PRIMA Project Management, it adds rules of its own and takes over the management of state-validation.md. See Rules It Installs.