What is plan mode in AI coding tools, and when should you use it?

What plan mode does

Coding agents normally read, edit and run things in one loop. Plan mode splits that loop in two: first the agent investigates and writes down what it intends to do, then you decide whether it goes ahead. The plan is the thing you review, instead of a diff that already touches a dozen files.

The three tools checked for this answer implement the same idea with different details. These descriptions come from each vendor's documentation as read on September 26, 2026.

• Claude Code: plan mode lets Claude read files and run shell commands to explore, and write a plan, but not edit your source until you approve. Enter it with Shift+Tab, by prefixing one prompt with /plan, or by starting with claude --permission-mode plan. When the plan is ready you can approve it into auto mode, approve it and review each edit manually, or keep planning. Ctrl+G opens the plan in your editor.
• OpenAI Codex CLI: typing /plan switches the active chat into plan mode, with optional inline text as the first planning request. The docs describe it as asking Codex to propose an execution plan before implementation starts. /plan is unavailable while Codex is already working.
• Cursor: Shift+Tab rotates the agent into Plan Mode, and Cursor may suggest it for prompts that look complex. The agent asks clarifying questions, researches the codebase, writes a plan you can edit in chat or as a markdown file, and builds only when you click to build. Plans are saved in your home directory unless you save them to the workspace.

When plan mode is worth it

Cursor's documentation recommends plan mode for complex features with several valid approaches, tasks that touch many files or systems, unclear requirements, and architectural decisions you want to review first. That matches the practical logic: the more a wrong assumption would spread through the code, the more a cheap review of the approach saves.

Plan mode also gives you a restart point. Cursor's docs suggest that when the agent builds the wrong thing, reverting and refining the plan is often faster than fixing the result with follow-up prompts. A saved plan is also something a teammate can read, which a chat transcript rarely is.

• Migrations, refactors and dependency upgrades that span many files.
• Features where you have not decided the data model or interface yet.
• Work in an unfamiliar codebase, where you want to see what the agent thinks the code does before it changes it.
• Changes that need sign-off from someone else before code is written.

When to skip it

Cursor's own docs say quick changes, or tasks you have done many times, can go straight to agent mode. Asking for a plan to rename a variable or fix a failing assertion adds a round trip without reducing much risk.

There is also a live argument that plan modes matter less as models improve. In an essay titled Plan mode is dead, published September 24, 2026, Ayman Nadeem, who built a planning-first coding app called Nuanced, argues that models now make more reasonable decisions on their own, that users had little appetite for reading long AI-written specs, and that choosing between a plan mode and a build mode adds cognitive load. The essay still argues that people need to understand what agents are changing; its claim is that a separate plan document is the wrong interface for that. This is one practitioner's experience, not a measured result, but it is a fair warning against treating plan mode as a default for everything.

Plan mode is not a sandbox

Plan mode stops file edits until you approve. It does not necessarily stop the agent from running commands. Claude Code's documentation says that while planning, shell commands are handled by the auto mode classifier when auto mode is available and the useAutoModeDuringPlan setting is on, which is the default, and otherwise prompt you unless they are in a built-in read-only set. In interactive terminal sessions with bypass permissions available, planning commands are not checked at all.

So if your concern is what an agent can reach, the controls are permissions, sandboxing and scoped credentials, not plan mode. Use plan mode to review the approach, and separate settings to limit what the agent can touch.

How to review a plan

A plan is only useful if you read it for the things that go wrong later. Aim to spend a few minutes on these points rather than on the prose.

• Scope: which files and systems does it plan to change, and is anything missing or unexpected?
• Assumptions: what does it believe about the existing code, and are those beliefs correct?
• Interfaces: does it change public APIs, schemas or configuration that other code depends on?
• Verification: which tests will it run or add, and how will you know it worked?
• Stopping points: for long plans, ask it to pause after each stage so you can check.

Limits of this answer

RepoRadar did not run hands-on tests of plan mode for this answer. Tool behavior is described from vendor documentation read on September 26, 2026, and these products change often, so check the current docs for your version. GitHub Copilot, Replit and other tools that search suggestions associate with plan mode were not checked here.

A useful next action

Pick your next change that touches more than a few files and run it once in plan mode. Before approving, check the plan against the review list above and note what you would have missed without it. If you corrected nothing, that kind of task probably does not need plan mode; if you corrected the approach, make plan mode your habit for that kind of change. Whichever you choose, set your permission mode on purpose, as our answer on Claude Code auto mode explains.