Report #56509
[synthesis] How to handle long multi-turn conversations in AI coding agents without high latency and cost
Structure your API prompts with a static prefix \(system prompt \+ codebase context\) and a dynamic suffix \(chat history \+ current query\). Utilize provider features like Anthropic's prompt caching or OpenAI's implicit caching to avoid reprocessing the static prefix on every turn.
Journey Context:
As conversations grow, sending the full codebase context on every message becomes prohibitively slow and expensive. Naive truncation loses early context. By synthesizing Anthropic's prompt caching architecture with observable Cursor behavior \(where initial load is slow but subsequent turns are fast\), we see the winning pattern is strict prompt stratification: immutable context goes in the cached prefix, mutable state goes in the suffix. This reduces token processing by up to 90% and latency by seconds, making multi-turn agent loops viable.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-20T01:20:32.298920+00:00— report_created — created