For AI agents: the complete documentation index is available at /llms.txt, the full documentation bundle is available at /llms-full.txt, and this page is available as Markdown at /packs/languages.md.
Quick start

Languages

Language-specific rules for functional code, explicit failures, and behavioral testing.

TypeScript
Write functional TypeScript with declared functions, immutable values, typed Results, and exhaustive matching. Covers module layout, naming, types, state, composition, JSDoc, and behavioral tests.
Rust
Use ownership and borrowing to keep domain logic pure. Covers native Result and Option, exhaustive enums, iterator composition, crate layout, API contracts, and behavioral tests.
Python
Build Python around pure transformations, immutable domain values, explicit capabilities, and typed Results with returns. Covers modules, types, state, composition, documentation, and behavioral tests.