project.every-domain-is-a-skill@1

What it is

URI

majordomus://rule/project.every-domain-is-a-skill@1

Kind

rule

Identity

project.every-domain-is-a-skill@1

Path

.ai/repo/rules/project/every-domain-is-a-skill.v1.md

Provenance

declared

Media type

text/markdown

As a capability

rule.project.every-domain-is-a-skill@1

Front matter

{
  "id": "project.every-domain-is-a-skill",
  "version": 1,
  "kind": "rule",
  "title": "Every domain of the registry is a skill, derived and shown wherever skills are",
  "description": "Each module of the capability registry with a public MCP tool is projected as one agent skill, /mj-<module>, generated from the registry, checked by generate --check, and listed by the site and the UI from the same projection.",
  "statement": "A skill an agent reads is derived from the registry or the layer's skills section, never written by hand, and every surface that lists skills reads the one projection that derives them.",
  "status": "active",
  "class": "blocking",
  "depends_on": [
    "project.interfaces-are-projections@1"
  ],
  "tags": [
    "architecture",
    "capabilities",
    "skills",
    "editors"
  ],
  "x-majordomus": {
    "tests": [
      "apps/majordomus-cli/src/editors/claude.rs",
      "test/cases/2980_a_capability_is_invoked_by_name_from_claude_code.sh",
      "scripts/site-check"
    ]
  }
}

Content

---
id: project.every-domain-is-a-skill
version: 1
kind: rule
title: Every domain of the registry is a skill, derived and shown wherever skills are
description: Each module of the capability registry with a public MCP tool is projected as one agent skill, /mj-<module>, generated from the registry, checked by generate --check, and listed by the site and the UI from the same projection.
statement: A skill an agent reads is derived from the registry or the layer's skills section, never written by hand, and every surface that lists skills reads the one projection that derives them.
status: active
class: blocking
depends_on: [project.interfaces-are-projections@1]
tags: [architecture, capabilities, skills, editors]

x-majordomus:
  tests: [apps/majordomus-cli/src/editors/claude.rs, test/cases/2980_a_capability_is_invoked_by_name_from_claude_code.sh, scripts/site-check]
---

# Rationale

A skill listing that shows some of what the repository offers teaches a person that the rest
does not exist. ADR 0165 derives one skill per domain of the registry so that the listing is
complete without being a copy of every tool, and so that adding a capability to a module is
the only act needed for it to be reachable by name.

# Required behaviour

The editors plan (`apps/majordomus-cli/src/editors/`) derives `.claude/skills/mj-<module>/SKILL.md`
for every module with a public capability that has an MCP tool, beside the command skills of
ADR 0146 and the workflow skills of the layer. No file under `.claude/skills/` is written by
hand: each carries the generated-file banner. The site's skills section and the UI list the
skills from `editors.status`, the projection the files are written from, and type no skill
name of their own.

# Failure behaviour

`majordomus generate --check` fails on a domain skill that is missing, stale or orphaned, and
the pre-commit hook runs it. The crate's tests in `editors/claude.rs` fail when a domain skill
loses a capability row, its effect, or the rule that a change runs only on the person's
request. `scripts/site-check` fails when the skills section lists a skill the projection does
not.

# Verification

`majordomus generate --check`, `majordomus editors status`, `cargo test --lib editors::`, and
`scripts/site-check`.