---
title: Rules and instructions
sidebar_title: Rules & instructions
description: Standing instructions every session reads before it touches code — conventions, preferences, the things you'd tell a new engineer on day one — with triggers, versions and a record of which task used which rule.
---

**Rules & instructions** are the things you would tell an engineer on their
first day: the conventions that aren't written down anywhere in the repository.
Every session loads the relevant rules before it touches code.

![The Rules & instructions page: "Rules every session loads before it touches code", an empty state, and an Add rule button](../assets/screens/rules.webp){ width="1600" height="184" }

## What makes a good rule

- *Use `pnpm`, never `npm`.*
- *All money is stored in minor units as integers.*
- *New endpoints need an OpenAPI entry and an integration test.*
- *Don't edit generated files under `src/gen/`; change the schema instead.*
- *UI copy is British English.*

Keep each rule to one idea. Short, specific rules are applied more reliably than
a long style guide.

## Account and repository rules

- **Account rules** apply to every repository.
- **Repository rules** apply only to one repository — its conventions, its
  gotchas.

## Standing and triggered rules

A rule without a trigger is **standing**: it is always eligible. A rule with a
**trigger** is used only when the session's goal and criteria match it — for
example, a migrations rule triggered by *migration* or *schema*.

Each session includes a bounded number of rules, preferring the most relevant,
so an enabled rule can still not reach a particular session. Keep rules focused
and use triggers for specialised ones.

## Versions and usage

- **Every edit creates a new version**; old versions stay visible.
- A session records **the exact version** of each rule it used, so an edit made
  later never changes what a past session was told.
- Each rule shows **which sessions used it**.

## Platform guidance

Alongside your rules, Ysra applies a small set of built-in guidance of its own.
It is read-only and listed under **Platform guidance** so you can see what it
says.

!!! tip "Rules versus memory"
    Rules guide **Developer** sessions. For facts and preferences you want
    carried across **Knowledge** conversations, use
    [Memory](../knowledge/memory.md).