Grep tool behavior

The Grep tool searches file contents for patterns. Where Glob finds files by name, Grep finds lines inside them.

Grep is built on ripgrep and uses ripgrep's regex syntax, not POSIX grep. Patterns that include regex metacharacters need escaping. For example, finding interface\{\} in Go code takes the pattern interface\\{\\}.

A pattern, glob, or file type that ripgrep rejects returns an error that includes ripgrep's diagnostic, so Claude can correct the input and search again. Before v2.1.208, Claude Code reported a rejected input as No files found instead of an error, even when the searched-for text existed in the target files.

Three output modes control what comes back:

• files_with_matches: file paths only, no line content. This is the default.
• content: matching lines with file and line number. When the tool's offset parameter points past the last match for a pattern that has matches, Grep returns No entries at this offset, so Claude widens or resets the offset instead of concluding the pattern doesn't match.
• count: match count per file, followed by a total across all matching files. The total covers every match even when the tool's head_limit or offset parameters truncate the listed per-file entries. Before v2.1.208, the total only summed the listed entries.

Claude can scope results by file with the glob parameter, such as **/*.tsx, or by language with the type parameter, such as py or rust. By default, patterns match within a single line. Claude can set multiline: true to match across line boundaries.

Grep respects .gitignore, so gitignored files are skipped. To search a gitignored file, Claude passes its path directly.

Claude Code decides permission for a Grep call before it checks whether the search path exists. It still runs the read-permission check for a missing path outside the working directories, so a permission prompt for a path doesn't mean the path exists.