Fan Out Across Files

For large migrations, split the work into many small Claude runs instead of one huge session.

Basic pattern

1. Generate a list of files.
2. Test the prompt on two or three files.
3. Refine the prompt.
4. Loop over the full list.
5. Verify with tests, lint, or a build.

Example

for file in $(cat files.txt); do
  claude -p "Migrate $file to the new API. Return OK or FAIL." \
    --allowedTools "Edit,Bash(npm test *)"
done

Why this helps

• Each file gets a smaller context.
• Failures are isolated.
• You can retry individual files.
• Permission scope can be limited with --allowedTools.

Guardrails

Keep destructive commands out of unattended fan-out workflows. Start with a tiny sample and review the diff before scaling up.