Start with a map
Identify the entry point, the relevant module, and the test closest to the behavior you want to understand. Explain how to run that part of the project. If you are unsure which files matter, ask for a read-only map first. This avoids turning an early guess into an instruction to edit the wrong module.
Include constraints with reasons
Name the interfaces that must stay compatible and the conventions the project already uses. Give a real input and expected output. Include the relevant error message with sensitive values removed. Distinguish current requirements from historical notes so the assistant does not implement an old plan as though it were still active.
Refresh before continuing
When a session resumes or the project changes, restate the current objective and inspect the working tree. Remove obsolete assumptions from the brief. A concise context handoff should explain the present state, completed checks, and next unresolved decision. The goal is enough evidence to work accurately, not an archive of every earlier exchange.
