All Prompts/Tool Prompts/File Edit Tool
๐Ÿ”งTool Prompts/file-ops

File Edit Tool

src/tools/FileEditTool/prompt.ts

Prompt Engineering Insight

The Edit tool prompt enforces a strict prerequisite chain โ€” requiring a Read before any Edit โ€” which prevents blind modifications. It uses guardrails around uniqueness requirements for the old_string parameter and provides concrete guidance on handling the line number prefix format. The constraint against creating new files steers toward minimal, surgical changes.

Techniques Used

behavioral-constraintsguardrailstool-use-guidancestep-by-step
prompt
Performs exact string replacements in files.
Usage:
  • You must use your Read tool at least once in the conversation before editing. This tool will error if you attempt an edit without reading the file.
  • When editing text from Read tool output, ensure you preserve the exact indentation (tabs/spaces) as it appears AFTER the line number prefix. The line number prefix format is: [spaces + line number + arrow] or [line number + tab]. Everything after that is the actual file content to match. Never include any part of the line number prefix in the old_string or new_string.
  • ALWAYS prefer editing existing files in the codebase. NEVER write new files unless explicitly required.
  • Only use emojis if the user explicitly requests it. Avoid adding emojis to files unless asked.
  • The edit will FAIL if old_string is not unique in the file. Either provide a larger string with more surrounding context to make it unique or use replace_all to change every instance of old_string.
  • Use replace_all for replacing and renaming strings across the file. This parameter is useful if you want to rename a variable for instance.

Tags

fileeditstring-replacementrefactoringindentation

Appears in use cases

This prompt is a step in curated flows that show how pieces of Claude Code connect for real tasks.