Use BEFORE the first Notion read or write on ANY task touching Notion — the Notion API or its MCP — however trivial: a one-field rename, a page icon/cover, adding one row, a single select color, even just reading a page's title. Covers creating, editing, querying, or moving databases, data sources, pages, views (table/board/gallery/calendar/timeline/list/chart/dashboard/map/form), formulas, rollups, relations, blocks, icons, covers; and any Notion API/MCP error (validation_error, pagination, permission, 400/409). MANDATORY, never optional — "small", "quick", "obvious", or "well-understood" is the exact trap: every Notion edit still owes this skill's mandatory first steps (the ancestral-AGENTS.md sweep + house-style match) that a direct quick edit silently skips and corrupts. If the work touches Notion at all, load this FIRST.
Use when naming anything — files, functions, types, variables, enum members — or choosing between a boolean, string union, and enum for a set of states. Triggers: a status/state field, vague or abbreviated names, single-letter values, Base-prefixed classes, Contract-suffixed interfaces, casing questions, PascalCase filenames, a name that covers only part of what the function does, a mechanism or pattern you invented a name for (a *Limiter/*Pool/*Gate) when the trade may already name it.
Use when about to write code against any external library, API, framework, or tool; when hitting an error, incompatibility, or unfamiliar technology; when introducing or naming a mechanism that solves a recognized problem (a limiter, pool, queue, retry/isolation primitive) even when its code is pure internal logic; before proposing a fix or presenting a design. Especially when confident from memory, under time pressure, when the API "is well known", or when a mechanism "is just internal logic".
Use when creating, splitting, or moving files; defining error classes or writing catch blocks; adding helpers, wrappers, or utils; structuring test files; or deciding where types, env vars, or server/client context live. Triggers: a file doing several things, circular imports, barrel files, a function that only forwards its arguments, a buildX(config) helper re-reading inputs a component already receives, an empty catch, a dense wall of code, inline multi-property object types, section-divider comments.
Use when creating any UI component, page, route, or layout, adding a prop to an existing one, wiring data fetching for a screen (prefetch, hydration, suspense, skeletons), or touching a component that has grown large — React or any component framework — plus forms, styling, and labels. Triggers: a prop toggling a section, a god component, dot-notation sub-components (Card.Header), raw inputs with hand-rolled validation, title-case labels, "just one more prop", a page marked "use client", a dataset passed as a prop to a client component, a route-level loading file, a page re-checking auth, a client-side re-parse of search params.
Use when defining domain types, database or validation schemas, config shapes, wire payloads, or translation/message trees; when adding a domain type, union member, registry, or dispatcher; when data is flat, joined by ID references, duplicated across fields, or its nesting does not match the real-world thing it describes. Distinct from glossary-style domain-modeling: this skill dictates STRUCTURE — isomorphism, containment, registries.
Use when developer experience is at stake — designing or reviewing any code structure, choosing between implementation approaches, extending existing code, or tempted to add abstraction, configuration, indirection, or generality. Triggers: over-engineering, speculative flexibility, "we might need it later", cognitive load, extension points, a growing conditional, "just add another branch/case/flag", clever code.
Use when working with André's self-hosted Google Workspace MCP (the `google-workspace` plugin) — driving Calendar, Gmail, Drive, Docs, Sheets, Slides, Forms, Tasks, Chat, or Contacts via the `mcp__plugin_maccing_workspace__*` tools, OR setting up / troubleshooting its OAuth (first-run consent, 7-day test-mode re-auth, credential storage). Covers the account-isolation rule (never use the `mcp__claude_ai_*` Google connectors — different account).