OpenClaw builds its own system prompt for every run; there is no runtime default prompt. What it builds is split by an internal cache boundary — the stable workspace prefix above, the per-turn channel context below — so backends with prefix caches can reuse the same prefix across channels.
Search found the right documents, but the LLM's answers are still poor — often the problem lies in prompt design. System prompt structure, context formatting, and instruction placement all affect output quality.