Video Summary

TanStack Code Mode — Rethinking AI Tool Calling

How reframing tool use as a single TypeScript code generation task slashes latency, cuts costs, and makes LLM math actually work.

The Problem

Traditional Tool Calling Is Broken

LLMs write great TypeScript but stumble on tool orchestration and math, creating bottlenecks.

Multiple sequential round trips between LLM and tools
Context window bloat with every tool description
Inaccurate mathematical calculations from the model
High latency compounds with each additional call

The Solution

Code Mode: Write Once, Run Sandboxed

Instead of step-by-step tool calls, the LLM generates a single TypeScript program that orchestrates everything — then executes it in an isolated sandbox.

One LLM call generates all tool orchestration code
Code runs in a sandboxed environment with tool access
Math happens in real TypeScript, not model guessing
Drastically fewer tokens, drastically lower latency

Side by Side: Call Patterns

See how Code Mode collapses a multi-turn interaction into a single generation step.

Traditional Tool Calling

1LLM reads query + tool descriptions
2LLM calls Tool A → waits for result
3LLM processes result, calls Tool B
4LLM synthesizes final answer

→

TanStack Code Mode

1LLM writes TypeScript that calls tools + does math
2Code runs in sandbox → final result returned

Measured Performance Gains

Real benchmarks from the video comparing traditional tool calling vs. Code Mode on the same query.

LLM Calls

4 → 2

50% fewer round trips

Context Used

9.8 KB → 1.7 KB

~83% context reduction

Response Time

27 s → 8 s

~70% faster responses

Key Takeaways

The biggest ideas from the video, distilled.

✓

Accurate Math, Finally

Offloading calculations to actual TypeScript means results like average prices are precise — no more LLM-guessed approximations.

⟳

Code Mode Skills

Persist generated TypeScript as reusable tools. Repeat queries drop to 2 calls, 0.5 KB, 3 seconds — the code is cached and ready.

⬡

Extensible by Design

Works with databases (generate SQL + TypeScript), combines with traditional tools, and models everything as a standard TanStack AI tool.

◫

Dynamic UI Reports

Code Mode can dynamically build UI reports on the fly — the LLM writes code that renders components, not just data.

The Core Idea

Instead of chaining tool calls, the LLM generates a single function that does everything.

          
          code-mode-example.ts
        
          // The LLM generates THIS as a single tool call:

          const result = await executeInSandbox(async ({ tools }) => {

            const products = await tools.searchProducts({ category: "electronics" });

            const prices = products.map(p => p.price);

            // Real math, not LLM approximation:

            const avg = prices.reduce((a, b) => a + b, 0) / prices.length;

            return { products, averagePrice: avg, count: products.length };

          });