start-core/execution-model

Configure isomorphic execution for TanStack Start server and client functions.

Updated Aug 23, 2026

Search Tags:#routing #server #environment-variables #client #tanstack-start #isomorphic #execution-model

Ready to run

npx skills add https://github.com/redacharf/fin-punk --skill start-core-execution-model-redacharf

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: start-core/execution-model
Source: https://github.com/redacharf/fin-punk/tree/main/.agents/skills/start-core/execution-model
Command: npx skills add https://github.com/redacharf/fin-punk --skill start-core-execution-model-redacharf

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Isomorphic-by-default execution: ensure code runs in both server and client bundles safely, preventing secret leakage and misused environment access.

Core Features & Use Cases

Isomorphic-by-default execution model with environment boundary controls for common TanStack Start patterns.
APIs: createServerFn, createServerOnlyFn, createClientOnlyFn, createIsomorphicFn, ClientOnly, useHydrated.
Guidance on handling environment variables and securing server-only data.

Quick Start

Implement a simple server-bound data fetch by wrapping it with createServerFn and call it from the client to observe the RPC pattern.

Frequently Asked Questions about start-core/execution-model

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I handle isomorphic code execution in TanStack Start to prevent server secret leakage?▼

To create a server-only data fetch in TanStack Start, wrap your logic with createServerFn and call it from the client to utilize the built-in RPC pattern, ensuring the execution remains securely on the server while returning data to the client.

What is the difference between createServerOnlyFn, createClientOnlyFn, and createIsomorphicFn in TanStack Start?▼

createServerOnlyFn restricts execution to the server bundle, createClientOnlyFn restricts it to the client, and createIsomorphicFn allows you to define separate implementations for both environments within a single function declaration.

How do I safely access environment variables in TanStack Start without exposing server secrets?▼

Safely access environment variables by following VITE_ prefix rules for client-exposed variables and using process.env for server-only secrets, combined with server-only functions to prevent accidental leakage during isomorphic rendering.

When should I use ClientOnly and useHydrated instead of createIsomorphicFn for TanStack Start components?▼

Use ClientOnly and useHydrated when you need to render specific UI components exclusively after client-side hydration, whereas createIsomorphicFn is better suited for branching data fetching or route loader logic across server and client environments.

Does TanStack Start route loaders support createServerFn for secure server-side data fetching?▼

Yes, TanStack Start route loaders support createServerFn, allowing you to execute secure server-side data fetching before rendering, which safely provides data to the client during SSR and subsequent client-side navigations.