On a metered API key, token waste shows up as a bill. On a subscription plan, Claude Code, Codex, "5x" and "20x" tiers, it shows up as a lockout.
You are halfway through a real task. The agent has the repo in its head, a failing test in front of it, and enough context to make the next edit. Then it stops. No useful warning. No obvious culprit. Just a usage wall.
The frustrating part is that the thing that burned the window was probably not the work itself. It was repeated context, cache misses, tool schemas, oversized models, and long sessions carrying old state forward.
Most token waste in coding agents is mechanical. Fixing it starts with understanding how context gets sent, cached, repeated, and billed.
The mental model
