Cost

Treating the context window as append-only memory is how agents get slow, expensive, and quietly wrong. The fix is to run it like a cache with a budget and an eviction policy: decide what earns its tokens every turn. Here’s the cost math, the accuracy failure mode, and a working context manager.

Retries feel cheap and local. In a multi-step agent they’re neither. A small cost model shows why 20% per-step failure can more than double your bill — and how your recovery architecture, not your failure rate, decides the multiplier.