# Documenter — F-004 Typed config and feature flags

done -> work/artifacts/F-004/documenter.md

## Why documentation applies
F-004 changes the startup contract (DATABASE_URL now required, fail-fast behavior) and introduces the flag mechanism every future risky feature will use.

## Documents reviewed/produced
- `project/README.md`: "Configuration" section added at build stage — required/optional vars, fail-fast behavior, FLAG_* semantics, fail-safe defaults, activation ≠ deployment.
- `.env.example`: REDIS_URL + FLAG_EXAMPLE_FEATURE added with explanatory comments.
- `spec/tech.md`: no new dependency rows needed — ticket added zero dependencies by design (noted for audit trail).
- `specs/F-004-config-flags/` SPEC/DESIGN/TASKS/TESTS consistent with implementation.

## Verification
- README Configuration section cross-checked against config.ts behavior (required DATABASE_URL; PORT/HOST/LOG_LEVEL/NODE_ENV/REDIS_URL defaults; FLAG_* parsing).
- Startup contract change (DATABASE_URL required) is called out explicitly so operators are not surprised.

## Pending docs (not this ticket)
- Flag admin transport documented when first consumer lands.