TanStack Start

Use this skill to apply current, source-backed TanStack guidance. Keep answers aligned with installed package source first, official TanStack docs second, and package-shipped skills third. Read references/current-authority.md when APIs, versions, CLI commands, or source freshness materially affect the task.

Decision Tree

• Need DB, secret, filesystem, or private API work? Use a server function or server route; never put it directly in a loader.
• Need same-origin app RPC? Use createServerFn(...).validator(...).handler(...).
• Need public or cross-origin HTTP? Use Start server routes through route server.handlers.
• Need auth? Enforce it in server functions/routes or middleware; beforeLoad is UX only.
• Need to know where code runs? Read rules/execution-model.md before designing loaders.

Rules

• rules/auth-boundaries.md
• rules/deployment.md
• rules/error-handling.md
• rules/execution-model.md
• rules/file-organization.md
• rules/input-validation.md
• rules/middleware.md
• rules/selective-ssr.md
• rules/server-functions.md
• rules/server-routes.md

Cross-Stack Cautions

• In TanStack Start apps, loaders are isomorphic; server-only work belongs behind server functions, server routes, or server-only modules.
• In Convex apps, Convex reactive queries own live backend state unless the repo intentionally routes through @convex-dev/react-query.
• In Clerk apps, Router guards improve UX but server functions, server routes, and Convex functions must enforce authorization.
• In Bun-first repos, prefer Bun commands for local workflow examples unless quoting official docs.

Verification

• Check exact installed package versions and source when behavior is version-sensitive.
• Use tanstack search-docs ... --json or tanstack doc ... --json for official docs lookup when the CLI is installed.
• Run the repo's typecheck, route generation, and relevant tests after implementing guidance.
• For skill maintenance, run python3 tools/skill/quick_validate.py skills/tanstack-start and python3 tools/skill/check_tanstack_skills.py --root . from dev-skills.