Plan mode
A mode where the agent can read and explore but can't edit your source files. It writes a plan, you read and change it, and only then does the work start.
A wrong plan takes a minute to fix, and a wrong diff can take an hour to unpick. It is also the cheapest moment to find out the agent misunderstood you. People do skip it: Elicit's interviewers report that "Plan-first thinking is rarer than we expected."
Say it to your agent
“/plan Add rate limiting to /api/login. Read the existing middleware first. Give me the files you would change, the test you would write first, and what you are unsure about. Do not edit anything.”