One long AI thread vs switching tools by stage

A workflow debate about staying in one context-rich thread versus switching tools when work changes stage.

There is a tension between keeping one long AI thread and switching tools by stage. One thread preserves context and constraints. But some stages need different capabilities: code execution, browser checks, official-doc lookup, cheap bulk drafts, or independent review. The switch is only worth it if the handoff is clear enough that the new tool does not re-litigate the whole task. Do you prefer one context-rich thread, or a portfolio where each tool has a narrow job?