Every Vera program that uses Result, Option, or UrlParts must locally redefine the ADT to access its constructors for pattern matching:

private data Result<T, E> { Ok(T), Err(E) }
private data Option<T> { None, Some(T) }

This is 2–6 lines of identical boilerplate in every program. All 9 examples that use these types include these definitions. The v0.0.88 viability assessment flags this as boilerplate that agents "will almost certainly forget" — the type checker registers the built-in constructors (environment.py lines 145–200) but the local data declaration is still required for pattern matching.

Design tension

Goal 2 (explicitness over convenience) argues against implicit imports. But this boilerplate adds no information — every definition is identical, and omitting it produces a confusing error rather than a useful explicitness signal.

Options to consider

1. Implicit prelude — Result, Option, and their constructors are always available without declaration (like Rust's std::prelude). Simplest for agents, least explicit.
2. Auto-import from vera.collections — the module vera/collections.vera already defines these types publicly. Making it auto-imported would provide the constructors without local redefinition.
3. Built-in constructor resolution — extend the checker so that constructors registered via environment.py are directly usable in patterns without a local data block. The type is already registered; only the constructor names are inaccessible.
4. Status quo with better docs — keep the redefinition requirement but improve SKILL.md templates to always include the boilerplate.

The vera.collections module already exists (examples/vera/collections.vera) and defines Option and Result publicly. A prelude that auto-imports this module would reuse existing infrastructure.

Cross-references

• Option and Result combinators #211 (combinators need Result/Option to already be available)
• JSON standard library type #58 (JSON type will add another ADT that programs need)
• Standard library collections (Set, Map, Decimal) #62 (Map/Set will add more standard ADTs)