agent-orchestration

lesson

llm-cost prompt-caching cache-amplification subagents vision agent-orchestration multimodal

382 tok

Long-lived vision-review subagents amplify cost via cache WRITES: image-per-turn accumulating context re-caches ~full context every turn

Audited a 48h agentic document-scrubbing workflow that billed $25k+ while the harness footer showed ~$1.1k. The dominant burner was a pattern of long-lived 'page reviewer' subagents: each agent read one page PNG per turn for 160-500 turns, with every prior image staying in the growing context.…

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