How TypeScript runs
The platform stores your original source. Node.js 24 removes type annotations immediately before execution, without a separate build step or generated JavaScript files on disk. Interfaces, type aliases, generics and satisfies add no runtime work. Enums, namespaces containing values and constructor parameter properties use Node.js built-in transformation.
Validation and execution serve different purposes. Native TypeScript 7.0.2 checks source with strict and the ES2024 standard library. Diagnostics include the original line, a TS… code and a description. Invalid code can be saved as a draft, but cannot be published or executed. If validation is unavailable, publication remains blocked. Checking types does not execute your code or contact the source website.
Available APIs
Standard collections, strings, numbers, dates, promises, URL, TextEncoder and TextDecoder are available. Use the SDK for HTTP, browser actions, HTML, documents, email, state, S3 and AI. Agents use the same APIs and restrictions. Error locations refer to original TypeScript, including after enum transformation.
This is a scenario runtime, not an arbitrary Node.js project. npm packages, imports, exports, require, process, filesystem operations and direct fetch are unavailable. SDK types are global and need no import. JSX/TSX, decorators, external reference directives, custom tsconfig files and path aliases are unsupported. Use ctx.http(), ctx.documents() and ctx.storage() instead of direct I/O.
Types do not verify external data at runtime. Check JSON fields and worksheet values before saving, and test your scenario.
Agents
Enable TypeScript when creating an agent. JavaScript and TypeScript share one runtime container, while language permissions remain separate. A TypeScript-only agent is not allowed to execute JavaScript scenarios. An older agent that does not report TypeScript support cannot receive such a scenario: generate a compatible bundle and update it. Enable browser support separately for interactive websites.
Trial runs, production runs, logs, cancellation and replay follow the JavaScript workflow. Breakpoint debugging is available only for PHP; use logs, ctx.log(), ctx.progress() and small trial runs for TypeScript.