App business logic documentation (English)

Purpose

Keep a single English narrative so humans (and future LLM turns) can understand what the app does and why, without reading every file.

Canonical file: docs/en/business-logic.md
Create docs/en/ if it does not exist.

When to use this skill

1. After business-logic changes — routes, validation, state machines, permissions, multi-step flows, integrations, or copy that reflects real rules.
2. Revalidation — the user asks to refresh the doc from the codebase, or debugging shows the doc (or mental model) is wrong or stale.
3. Onboarding — initial fill after an app or app reaches a coherent shape.

Do not treat this as API reference: no exhaustive endpoint lists unless they carry domain meaning. Prefer flows, invariants, and “if user does X then Y”.

Document structure (adapt as needed)

Use clear headings, for example:

• Product overview — who uses it, primary job-to-be-done.
• Glossary — domain terms.
• Actors & roles — visitor, member, admin, system, etc., aligned with real authz.
• Main scenarios — numbered happy paths (step-by-step).
• Edge cases & failure behavior — errors, empty states, retries, idempotency.
• Data & ownership — what lives in dashboards vs Gate vs isolated stores (if any), at a conceptual level.
• Code map — short table: scenario or area → primary paths (apps/..., backend/...).

Workflow

1. Read the current docs/en/business-logic.md if present.
2. Inspect the code that implements the changed or unclear behavior (apps, backend/, shared libs).
3. Update the doc so it matches observable behavior, not intentions that are not implemented.
4. If behavior is ambiguous, state the ambiguity and what you verified in code or runtime.

Quality bar

• Short paragraphs, concrete examples, no filler.
• A new teammate should follow main scenarios without opening the repo.
• When revalidating during debug, add a “Debugging notes” subsection with dated bullets if it helps (optional).

Flag

This skill is copied into the project only when the global CLI flag app-business-docs is enabled (fusebase config set-flag app-business-docs then fusebase update --skip-mcp --skip-deps --skip-cli-update --skip-commit).