For anything bigger than a one-file fix, Plan Mode lets you catch a wrong assumption before any file has actually changed.
1A Plan Is Cheaper to Fix Than a Diff
Catching a missing step or wrong assumption in a five-line plan takes seconds. Catching the same problem after it's spread across five edited files, with tests already run, costs far more — undoing partial work, re-explaining the correction, and re-verifying. Plan Mode moves the review earlier, where it's cheapest.
2Reviewing a Plan Is the Same Discipline as Reviewing a Diff
Approving a plan without actually checking it against the original spec defeats its purpose. The same habit from reviewing AI-generated code — checking each requirement was actually addressed — applies here, just one step earlier in the process.
3Step-by-Step Breakdown
The Export Feature Touches More Than One File. features/export.md describes a real feature: export tasks as CSV, reusing sumTaskHours, with a new route, a new UI button, and new tests. That's too large to just start editing — this is exactly the kind of task where Plan Mode earns its keep.
Plan Mode: Propose Before Touching Anything. In Plan Mode, Claude Code reads the relevant files and the spec, then writes out its intended approach — which files it'll create or change, and in what order — without editing anything yet. You read the plan, catch anything wrong, and only then approve it to start acting.
What's the main advantage of reviewing a plan before Claude Code starts editing, versus letting it start editing immediately on a multi-file feature?
- →You can catch a wrong assumption or missing step while it's still just a list of steps, before any files have actually been changed — cheaper to fix than after five files are already edited.
- →Plan Mode makes Claude Code respond noticeably faster.
Review a Plan Like a Reviewer, Not a Rubber Stamp. Given the export feature's plan above, decide whether it's actually complete against the spec in features/export.md, and identify anything missing before approving it.
Approve, Then the Loop Runs. Once you approve the plan, Claude Code executes it step by step — reading, editing, and verifying each part, still asking permission for risky actions along the way. Next module: the core day-to-day workflow — debugging, refactoring, and generating tests you can actually trust.
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Browser Support
N/A — Plan Mode is a CLI session mode.
N/A — Plan Mode is a CLI session mode.
N/A — Plan Mode is a CLI session mode.
N/A — Plan Mode is a CLI session mode.
Accessibility (A11y)
1Plans Are Numbered Lists, Not Diagrams
Plan Mode's output is plain, sequential text — straightforward to read with a screen reader and easy to reference step-by-step when giving feedback ('step 3 is missing the failure case').
SEO Implications
- 1
Target 'Claude Code Plan Mode explained' and 'reviewing an AI coding plan' separately
Users search for what the feature is and for how to actually review its output effectively as distinct questions.
Best Practices
Check the Plan Against the Original Spec, Line by Line
Before approving, walk through each requirement in the spec and confirm the plan actually addresses it — the same discipline used to review generated code, applied one step earlier.
Frequent Bugs
Approving a plan on sight because it 'looks reasonable,' without checking it against the actual spec or requirements.
Read the plan against the original requirement list explicitly — treat any unaddressed requirement as a gap to raise before approving, not an acceptable omission.
Real-World Examples
The Missing Failure Case
A plan for the export feature covered the normal and empty-list cases but silently dropped the failure-handling requirement from the spec. Catching it during plan review meant one added line to the plan — catching it after implementation would have meant editing an already-written route handler and its tests.
// Plan review caught it:
// "add step: handle export failure with a clear error response"