Grep

The Grep tool searches file contents using regular expression pattern matching. It is similar to the Unix grep command but optimized for use by the AI.

What It Does

• Searches one or more files for lines matching a pattern
• Supports regular expressions
• Returns matching lines with file paths and line numbers
• Can search recursively through directories

When It’s Used

The AI uses Grep when:

• It needs to find all usages of a function, variable, or symbol across a codebase
• You ask it to locate specific content in files
• It’s exploring a project and needs to understand how pieces connect

Example

“Find all places in this project where the authenticate function is called.”

The AI will run a Grep search for authenticate across the relevant source files and report all occurrences with their file paths and line numbers.

Tips

• Grep is most effective when combined with Glob — Glob finds files, Grep searches within them
• For simple file searches, Glob alone is faster
• Regular expression patterns give precise control over what’s matched