What a pattern definition looks like. Each pattern is a single YAML file organized by category.

Example: scaffolding/project.yaml

# Pattern: Fastblocks project skeleton
id: scaffolding/project
name: Fastblocks Project Skeleton
description: Base project structure with Oneiric config, entry point, and settings
version: 1.0
source_repos: [fastblocks, splashstand]  # where this pattern was learned from
confidence: 0.95  # how consistently this pattern appears across repos
depends: []  # no dependencies — this is the base pattern

structure:
  dirs:
    - path: settings/
      required: true
    - path: templates/base/blocks/
      required: true
    - path: templates/pages/
      required: false
    - path: adapters/
      required: false
    - path: static/
      required: false

  files:
    - path: main.py
      required: true
      template: entry-point  # references a Jinja template
    - path: pyproject.toml
      required: true
      template: pyproject
    - path: settings/app.yml
      required: true
      template: settings-app
    - path: settings/adapters.yml
      required: false
      template: settings-adapters

templates:  # Jinja templates for file generation
  entry-point: |
    from starlette.routing import Route
    from oneiric.core.resolution import Resolver

    depends = Resolver()

    def resolve_dep(key):
        candidate = depends.resolve("{{ project_name }}", key)
        if candidate is None:
            raise RuntimeError(f"Missing dependency: {key}")
        factory = getattr(candidate, "factory", None)
        return factory() if callable(factory) else candidate

    routes = [Route("/", endpoint=homepage)]
    app = resolve_dep("app")
  pyproject: |
    [project]
    name = "{{ project_name }}"
    requires-python = ">=3.12"
    dependencies = [
        "fastblocks",
        "oneiric",
    ]
  settings-app: |
    app:
      name: "{{ project_name }}"
      title: "{{ project_title }}"
      debug: true

slots:  # extension points for component patterns
  - nav: templates/base/blocks/  # navigation pattern plugs in here
  - auth: adapters/              # auth pattern plugs in here
  - middleware: main.py          # middleware pattern modifies entry point

Key design decisions:

structure.dirs — defines the directory skeleton. required: true means every generated project gets this directory.
structure.files — defines files with Jinja templates for content generation. Templates use {{ project_name }} variables.
slots — named extension points where component patterns plug in. The nav slot means "the navigation component pattern writes its files into this directory."
source_repos — provenance: where this pattern was learned from. Enables "show me patterns used in Splashstand."
depends — patterns this pattern requires. An auth.yaml pattern would depend on scaffolding/project.yaml.

Pattern Library — YAML Format