Keep Every LangSmith Trace Without the 10 Retention Bill

LangSmith is excellent for debugging live AI systems. But keeping every trace in its extended-retention tier can turn observability into a surprisingly large line item. Today we merged a new archive workflow into langsmith-cli that changes that tradeoff: keep LangSmith for live debugging, continuously archive verified traces to organization-owned private S3, and query the retained Parquet directly with DuckDB. In other words, you can preserve your complete trace history without placing every trace on LangSmith's extended-retention tier. The cost-overrun risk LangSmith currently documents two trace-retention tiers: Tier Retention Published trace price Base 14 days 0.05¢ Extended 400 days 0.50¢ total The 0.45¢ extended-retention upgrade makes an extended trace cost 10× as much as a base trace. That difference becomes material at production volume: Monthly traces Base, 14 days Extended, 400 days Added retention cost 100,000 $50 $500 $450 1,000,00