Rules

rules/ holds the conventions an agent must follow without being asked: commit format, error handling, the money type, the test style. Each tool loads rules on its own terms (Cursor .mdc files, Claude Code rules, AGENTS.md sections); a rule spec is written once and lands in each.

Always on, or only where it matters. A rule can apply to every session, to one directory, or to files that match a pattern, so a payments convention stays out of frontend work.
Close to the code. A rule under rules/services/payments/ applies inside services/payments/, and supported tools load it only there.
Checked like code. sync --check fails when a tool's copy drifts from the spec, and agnostic-ai explain --file <path> lists which rules apply to a file.

Keep a rule short and stated as an instruction. Put a multi-step procedure in a skill instead, so it loads only when needed.

Write one

agnostic-ai new rule conventional-commits creates rules/conventional-commits.md with globs: "**/*" and alwaysApply: true.

---
name: conventional-commits
description: Always use Conventional Commits format.
globs: "**/*"
alwaysApply: true
---

Use `feat:`, `fix:`, `docs:`, etc. Subject under 72 chars.

A rule for one file type, loaded when the agent works on matching files:

---
name: react-components
description: Conventions for React components.
globs: "src/**/*.{ts,tsx}"
---

Write function components. Keep one exported component per file.

A rule for one directory. agnostic-ai new rule payments-context --scope services/payments creates it, or place the file at rules/services/payments/payments-context.md:

---
name: payments-context
scope: services/payments
---

Use integer minor units for monetary values.

Claude Code gets a conditional rule. Codex and Cursor share services/payments/AGENTS.md. Gemini gets services/payments/GEMINI.md. See directory-specific instructions for every target and the selector limits.

Fields

Field	Required	Default	Description
`name`	no	filename	Rule identifier.
`description`	no	empty	Short summary.
`scope`	no	project-wide	Project-relative directory and its descendants. Source-layout scope wins. A scope inside `node_modules` is refused. See scoped context.
`globs`	no	target-dependent; `new rule` seeds `*/`	Project-relative patterns, as a comma-separated string (`".go,.mod"`) or a list. A comma inside a brace set does not separate patterns, so `"src/*/.{ts,tsx}"` is one pattern. With `scope`, the selector must stay inside the directory. `new rule --scope` omits it.
`paths`	no	unset	File patterns, as a string or list. Scoped rules accept it with or instead of `globs`; see selector limits.
`alwaysApply`	no	target-dependent; `new rule` seeds `true`	Requests unconditional activation. With `scope`, only inside the directory. `new rule --scope` omits it.

Tools differ on what a rule with neither globs nor alwaysApply does; each target page says how it activates. Set alwaysApply: true when a rule must load everywhere.