Design, build, verify, and publish production-grade TypeScript SDKs as npm packages inside a pnpm monorepo. Covers workspace layout, public API and module boundaries, plugin extension points, branded types and library-tuned tsconfig, tsdown bundling (vs tsup/tsc-only/unbuild), package.json exports with dual ESM+CJS and isomorphic conditions (browser/workers/RN/deno), Turborepo pipelines, publint and @arethetypeswrong/cli verification, changesets pre-release mode, npm dist-tags (latest/next/beta/rc/canary), and the alpha→beta→rc→stable release lifecycle. Triggers on: build a TS SDK, extract core library, package.json exports, dual ESM CJS, tsdown config, tsup vs tsdown, publint, attw, changesets prerelease, npm dist-tag, beta to rc, canary release, pnpm workspace SDK, isomorphic SDK, tsconfig library, npm provenance, shipping a TypeScript library.