AI agent glossary
Plan mode
A coding agent setting where the agent may read and explore but not edit files, so it proposes a plan for you to approve before making changes.
Plan mode separates thinking from doing. While it is on, the agent can read files, search the codebase, and ask questions, but it cannot modify anything. It finishes by presenting a step-by-step plan, which you can accept, edit, or reject before any code changes.
Claude Code offers a plan mode, and other coding agents provide similar read-only or planning modes. Even without a dedicated mode, you can get the same effect by asking the agent to explore and propose a plan before writing code.
Planning first catches misunderstandings while they are cheap to fix. Reviewing a short plan takes a minute; untangling a large diff built on a wrong assumption can take an hour. It is most valuable for tasks that touch several files or where the right approach is not obvious.
You ask an agent in plan mode to add CSV export to a reports page. Its plan reveals it intends to write a new CSV library, so you point it at the one already in the project before it writes a line.
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