ttsc

ttsc is an open-source toolchain built on TypeScript-Go (typescript-go) by Jeongho Nam, the author of typia and nestia. It acts as a drop-in replacement for tsc that reads the same tsconfig.json, accepts the same flags, and runs compiler plugins in the same pass that type-checks the project. The latest GitHub release listed is v0.36.3.

What It Is

ttsc is a compiler-centered toolchain for TypeScript projects. The ttsc command builds, checks, watches, and transforms code, while ttsx runs a TypeScript entrypoint only after the owning project passes type-check. Related packages add linting and formatting, requirement coverage, a code graph for coding agents, and a plugin host. It requires typescript 7.0 or later installed alongside it.

One diagnostic stream

@ttsc/lint reports lint rules as TypeScript diagnostics, so type errors and rule violations appear together in local runs, CI, and the editor. The docs describe 720+ rules across 21 families plus a formatter ported from Prettier. npx ttsc fix applies autofixes and formatting, and npx ttsc format only formats. The project states that lint runs much faster than ESLint because rules reuse the AST and types the compiler has already built.

Evidence Graph for requirements

@ttsc/evidence turns specification items into compile-time obligations. Each configured requirement must be acknowledged by name through an @evidence tag in code, tests, or documents, or the build fails with a diagnostic. The project positions this so AI coding agents cannot finish while requirements stand unanswered, and publishes benchmark results of its own for coverage.

Compiler Knowledge Graph for agents

@ttsc/graph is an MCP server that exposes a checker-resolved graph of a project to coding agents, so they query the compiler rather than grepping and re-reading files. Setup is a .mcp.json entry that runs npx -y @ttsc/graph. The project reports about 90% token savings in its own benchmarks.

Plugins and integrations

Plugins run beside the TypeScript-Go AST and Checker to report diagnostics or rewrite source before emit. First-party plugins include @ttsc/banner, @ttsc/paths, and @ttsc/strip, and ecosystem plugins include typia and nestia. Integrations cover bundlers through @ttsc/unplugin, React Native and Expo through @ttsc/metro, a VS Code plugin, and a browser playground built on a WebAssembly build.