Read a UTF-8 text file under the workspace. Use before editing when content is unknown. Optional start_line/end_line (1-based inclusive). Optional max_bytes override.

Write or append UTF-8 text under the workspace. Mode: overwrite or append. Creates parent dirs. Do not use without reading first unless you are creating a new file or already hold exact contents.

Search-and-replace in an existing UTF-8 file: old_string must be non-empty and match exactly once unless replace_all is true. Read the file first and copy the exact span. Output uses newline='\n' like write_file.

Run a subprocess with argv list only (no shell). Optional cwd relative to workspace or absolute path under root. Use only when necessary; prefer read/list for inspection.

List files and directories under a workspace path. Optional recursive, glob_pattern, max_depth, include_dotfiles. Use to discover layout before reading.