Async Python

Essential for parallel tool calls and streaming in agent systems.

import asyncio

# Run multiple tool calls in parallel
async def parallel_tools(tasks):
    results = await asyncio.gather(
        fetch_weather("NYC"),
        fetch_stock("GOOG"),
        fetch_news("AI"),
    )
    return results

# Semaphore for rate limiting
sem = asyncio.Semaphore(5)  # max 5 concurrent calls
async def limited_call(url):
    async with sem:
        return await fetch(url)

# When to use async vs sync
# Async: I/O bound (API calls, DB queries, file reads)
# Sync:  CPU bound (data processing, math)