> For AI agents: the complete documentation index is available at /llms.txt, the full documentation bundle is available at /llms-full.txt.

# Languages

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


[TypeScriptWrite functional TypeScript with declared functions, immutable values, typed Results, and exhaustive matching. Covers module layout, naming, types, state, composition, JSDoc, and behavioral tests.](/packs/languages/typescript)[RustUse ownership and borrowing to keep domain logic pure. Covers native Result and Option, exhaustive enums, iterator composition, crate layout, API contracts, and behavioral tests.](/packs/languages/rust)[PythonBuild Python around pure transformations, immutable domain values, explicit capabilities, and typed Results with returns. Covers modules, types, state, composition, documentation, and behavioral tests.](/packs/languages/python)