CCARF Practice Question

Paper 1 · Question 21

D2 Tool Design & MCP Integration · Paper 1

A developer needs to rename a variable from 'userData' to 'customerData' in a specific file. The variable appears 12 times throughout the file. What is the most efficient approach using Claude Code's built-in tools?

• A.Use Grep to find all 12 occurrences, then call Edit 12 times, once for each occurrence with unique surrounding context.
• B.Use Read to load the file, then Write the entire file back with all occurrences manually changed.
• C.Use Edit with replace_all set to true, specifying 'userData' as the old string and 'customerData' as the new string.
• D.Use Bash with sed to perform a global find-and-replace across the file.

Show answer & explanations

Correct answer: C

A: Calling Edit 12 times is inefficient. The Edit tool's replace_all parameter is designed for exactly this use case — renaming a variable across an entire file in a single call.

B: Read + Write rewrites the entire file, which is wasteful for a simple rename. The Edit tool with replace_all handles this more efficiently by sending only the diff.

C: The Edit tool's replace_all parameter replaces all occurrences of the specified string in a single operation. This is the most efficient approach for renaming a variable throughout a file.

D: While sed can perform the replacement, the exam expects candidates to use built-in tools for file modifications. Edit with replace_all is the purpose-built tool for this task.

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