DataFunTalk

Nov 2, 2026 · Artificial Intelligence

LangChain Slashes 65% of Default Agent Harness: Why Less Prompt Means More Control

LangChain's Deep Agents v0.7 cuts default harness base input tokens by 65% — from 5,395 to 1,895 — by clearing the default system prompt, trimming tool descriptions 43%, and making TodoListMiddleware opt-in, backed by evaluations across GPT-5.6, Claude Opus 4.8, and GLM 5.2 showing no consistent accuracy gains from these components.