# North Star > Constitutional source of truth for reusable Plate architecture and public API design. Use when introducing or changing reusable public APIs, runtime/service boundaries, builder or factory patterns, extension registration contracts, naming/layering rules, or performance-sensitive architecture. - Skill: `lofcz/north-star` (Agent Skill, multi-file: 7 files) - Install (CLI): `npx skillmds@latest add lofcz/north-star` - Raw SKILL.md: https://api.skillmd.com/api/skills/lofcz/north-star/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Integrations & APIs - Author: lofcz (https://skillmd.com/u/lofcz) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/lofcz/north-star --- # North-Star Plate's constitutional doctrine for reusable architecture and public API design. Use this skill before shaping a reusable Plate surface. This is the upstream decision layer. It owns architecture law, public API shape, layering, performance/scalability selection, and anti-patterns. Use [plate-plugin-creator](../plate-plugin-creator/SKILL.md) after the public pattern is already chosen and the work has become plugin-authoring execution. ## Use When - Introducing or changing a reusable public API - Designing builder/factory patterns - Designing plugin/extension registration patterns - Designing runtime/service boundaries - Designing caches, projections, protocol layers, or service seams - Choosing between competing ergonomic vs performance shapes - Renaming or re-layering a reusable API family - The right owner or architectural layer is ambiguous ## Do Not Use When - The work is app-local convenience only - The work is a one-off migration helper with no durable public pattern - The public pattern is already settled and you are just implementing plugin mechanics - The question is only about public docs wording - The work is git/process workflow, not reusable API design ## Hard Routing Rule - If the work touches a reusable public/editor-platform API, use `north-star` first. - If the work touches runtime/service-boundary architecture, use `north-star` first. - If the work is ambiguous between reusable API design and implementation, route upward to `north-star` first. - If the work is app-local convenience only, do not use `north-star`. - If the public pattern is already settled and the task is plugin execution, hand off to [plate-plugin-creator](../plate-plugin-creator/SKILL.md). ## Routing Matrix | Scenario | Route | Why | | --- | --- | --- | | new reusable plugin public API | `north-star` first, then execution companion | public contract decision | | runtime/service boundary | `north-star` first | architecture/runtime law | | new builder/factory pattern | `north-star` first | reusable pattern decision | | reusable naming/layering rule | `north-star` first | doctrine | | wrapper/component implementation under settled doctrine | execution companion | mechanics only | | app-local registry-kit sugar | stay local | not reusable doctrine | | one-off docs/demo convenience | stay local | not reusable doctrine | | package-local mechanics only | execution companion | implementation lane | ## Who Owns What | Concern | Owner | | --- | --- | | reusable architecture doctrine | `north-star` | | public API shape decisions | `north-star` | | runtime/service-boundary patterns | `north-star` | | layering / ownership law | `north-star` | | performance/scalability law | `north-star` | | anti-pattern catalog | `north-star` | | plugin file placement / wrappers / typing mechanics | execution companion | | plugin authoring execution flow | execution companion | | app-local sugar | local app/kits | ## Constitutional Layer - [laws.md](./rules/laws.md) - [decision-ladder.md](./rules/decision-ladder.md) - [performance-selection-rules.md](./rules/performance-selection-rules.md) - [update-policy.md](./rules/update-policy.md) ## Pattern Layer - [pattern-catalog.md](./rules/pattern-catalog.md) - [anti-patterns.md](./rules/anti-patterns.md) ## Best Mix - ProseMirror/Tiptap: extension ownership and productized ergonomics - Portable Text: spec discipline, schema applicability, behavior authoring, and behavior-test standards - Lexical: runtime contracts and perf posture - Premirror/Pretext: layout and measurement as first-class architecture - urql/TanStack DB/LSP: pipeline, state, and service-boundary patterns - kitcn plus lighter editors: scoped builders where earned, restraint where not The concrete pattern guidance lives in [pattern-catalog.md](./rules/pattern-catalog.md). ## Matcher Extraction Heuristic When scanning a reusable API family, aggressively inspect repeated `resolve()` and `apply()` bodies before inventing more package-level wrappers. Default posture: - if multiple packages repeat the same **matching prelude**, that is pressure for a core primitive - if multiple packages repeat the same **feature action**, that usually still belongs in the owning package Pull into core when the repeated logic is mostly: - trigger gating - collapsed-selection gating - block-start / text-before / adjacent-char lookup - delimiter / prefix / regex matching - range or payload construction - other editor-state inspection that is feature-agnostic Keep local when the repeated logic is mostly: - node creation - mark toggling - list transforms - link validation or insertion - equation insertion - code-block insertion - any semantic transform owned by a feature package The goal is: - core owns matcher primitives and shared input-state access - feature packages own semantic apply behavior Do not flatten package semantics into core just because the files look similar. Do not miss a real core primitive because the action code is loud. ## Workflow 1. Run the [decision ladder](./rules/decision-ladder.md). 2. Decide the owner and layer first. 3. Check the [pattern catalog](./rules/pattern-catalog.md) for the preferred family. 4. Scan repeated `resolve()` / `apply()` shapes and separate matcher logic from feature semantics before blessing a new public helper. 5. Run the [performance selection protocol](./rules/performance-selection-rules.md) before blessing the prettier API. 6. Check the [anti-patterns](./rules/anti-patterns.md). 7. If the work introduces or materially changes a reusable public pattern, follow the [update policy](./rules/update-policy.md). 8. Once the pattern is chosen, hand off implementation mechanics to [plate-plugin-creator](../plate-plugin-creator/SKILL.md) or another more specific execution skill. ## Reaffirmation Contract Every lane that introduces or materially changes a reusable public API, runtime boundary, builder/factory pattern, or extension contract must include one of: - `north-star updated` - `north-star reaffirmed: ` Reaffirmation is not implicit. It must name the governing section so the claim is reviewable. Examples: - `north-star reaffirmed: laws` - `north-star reaffirmed: decision-ladder` - `north-star reaffirmed: performance-selection-rules` ## Binary Review Checklist 1. Is the owner named? 2. Is the layer named? 3. Is reusable vs local decided? 4. Is the governing `north-star` section named? 5. Was the performance protocol applied when hot-path relevant? ## Relationship To Other Skills - [plate-plugin-creator](../plate-plugin-creator/SKILL.md) - plugin-authoring execution companion - [docs-creator](../docs-creator/SKILL.md) - public docs companion - [react](../react/SKILL.md) - React implementation companion ## Final Law If a reusable API or runtime boundary matters to future Plate work, `north-star` decides the pattern. Local convenience, plugin mechanics, and documentation follow from that. Not the other way around.