Core concept: Claude Code's search tools split by what you are matching. Grep matches text inside files. Glob matches file names and paths. Each built-in tool has one job, and the right one is the cheapest one.

Why A and B are correct:

The docs describe Grep as the tool that "Searches file contents for patterns", built on ripgrep. Hunting every call site of a deprecated function name under src/ is exactly that job.
Grep can be scoped with its glob or type parameter and needs no permission prompt, so the sweep is fast and safe.
The docs describe Glob as the tool that "Finds files by name pattern", supporting ** for recursive matching. A pattern like **/*.test.tsx is the correct way to list those test files.

Why the others are wrong:

C: Write "Creates or overwrites files" and "should be used when creating new files". Overwriting a heavily documented config file to fix one typo risks dropping the rest of it. Edit "Makes targeted edits to specific files" and is the correct tool for a small change.
D: Shelling out to find duplicates Glob. Bash requires permission, returns raw unsorted output, and hides the search from the tools built for it.

Remember: Grep looks inside files, Glob looks for files. Never shell out for either.

Question 150