# Multi Language Feature Builder > Build multi-file features that span TypeScript and Python. Use when a feature requires changes in both languages. Use when this capability is needed. - Skill: `tomevault-io/multi-language-feature-builder` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/multi-language-feature-builder` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/multi-language-feature-builder/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/multi-language-feature-builder --- # Multi-Language Feature Builder When asked to implement a feature that touches both TypeScript and Python: 1. Identify the contract boundary (e.g., REST endpoint, shared schema, CLI interface) and agree on it before writing code in either language. 2. Implement the Python side first; write the TypeScript side to match the agreed contract. 3. Keep each language's code idiomatic — do not port Python patterns into TypeScript or vice versa. 4. Update both language's tests together; a feature is not done until tests pass in both. If the scope is unclear, ask for the entry point and expected output before starting. --- > Source: [complytime-labs/lola-eval](https://github.com/complytime-labs/lola-eval) — distributed by [TomeVault](https://tomevault.io).