# TanStack AI Tool Calling

> Isomorphic toolDefinition. Not OpenAI tools / Vercel tool()

**Subcategory:** TanStack  
**License:** MIT  
**Source:** https://github.com/TanStack/ai/blob/main/skills/ai-core/tool-calling/SKILL.md

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## When it is useful

Type-safe isomorphic tools via TanStack AI toolDefinition that can run on server or client. Not OpenAI tools arrays and not Vercel AI SDK tool(). Pinned 0.42.0.

## The Catch

Isomorphic toolDefinition. False-fires on OpenAI tools and Vercel tool(). Distinct from chat-experience. OSS SDK 0 USD; provider keys still required.