Ask Claude to Explain Code Before Editing It
Before you let Claude modify a function you don't fully understand, ask it to explain the code first. This one habit prevents a surprising number of silent regressions.
Explain what the `processPayment` function does and list any edge cases
it currently handles. Do not make any changes yet.
Claude will walk through the logic, call out side effects, and flag any assumptions baked into the code. Once you're aligned on what it actually does, you can give a much more precise instruction for what to change — and Claude won't have to guess at your intent.
The "do not make any changes yet" is key. Without it, Claude might start optimistically refactoring while explaining, which defeats the whole point.
# Step 1: understand
Explain what `calculateShipping` does and what assumptions it makes
about the input data. Do not edit anything.
# Step 2: change with confidence
Now update it to also handle international addresses, keeping all
existing domestic logic intact.
This pattern is especially valuable when working with code you inherited, code that hasn't been touched in years, or anything with unclear naming.
Understanding before editing is the difference between a surgical fix and an accidental rewrite.
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Before asking Claude to scaffold a new feature, point it at your existing code first — it will match your naming, structure, error handling, and test patterns exactly rather than defaulting to framework boilerplate.
Give Claude the full picture upfront before it writes any code, so it builds the right thing the first time with fewer correction rounds.
Complex prompts are unreadable as escaped single-liners. Use shell HEREDOCs to write clean, structured prompts directly in your scripts.