Function validateInput

src/tools/FileEditTool/FileEditTool.ts:137–362

(input: FileEditInput, toolUseContext: ToolUseContext)

  renderToolUseRejectedMessage,
  renderToolUseErrorMessage,
  async validateInput(input: FileEditInput, toolUseContext: ToolUseContext) {
    const { file_path, old_string, new_string, replace_all = false } = input
    // Use expandPath for consistent path normalization (especially on Windows
    // where "/" vs "\" can cause readFileState lookup mismatches)
    const fullFilePath = expandPath(file_path)

    // Reject edits to team memory files that introduce secrets
    const secretError = checkTeamMemSecrets(fullFilePath, new_string)
    if (secretError) {
      return { result: false, message: secretError, errorCode: 0 }
    }
    if (old_string === new_string) {
      return {
        result: false,
        behavior: 'ask',
        message:
          'No changes to make: old_string and new_string are exactly the same.',
        errorCode: 1,
      }
    }

    // Check if path should be ignored based on permission settings
    const appState = toolUseContext.getAppState()
    const denyRule = matchingRuleForInput(
      fullFilePath,
      appState.toolPermissionContext,
      'edit',
      'deny',
    )
    if (denyRule !== null) {
      return {
        result: false,
        behavior: 'ask',
        message:
          'File is in a directory that is denied by your permission settings.',
        errorCode: 2,
      }
    }

    // SECURITY: Skip filesystem operations for UNC paths to prevent NTLM credential leaks.
    // On Windows, fs.existsSync() on UNC paths triggers SMB authentication which could
    // leak credentials to malicious servers. Let the permission check handle UNC paths.
    if (fullFilePath.startsWith('\\\\') || fullFilePath.startsWith('//')) {
      return { result: true }
    }

    const fs = getFsImplementation()

    // Prevent OOM on multi-GB files.
    try {
      const { size } = await fs.stat(fullFilePath)
      if (size > MAX_EDIT_FILE_SIZE) {
        return {
          result: false,
          behavior: 'ask',
          message: `File is too large to edit (${formatFileSize(size)}). Maximum editable file size is ${formatFileSize(MAX_EDIT_FILE_SIZE)}.`,
          errorCode: 10,
        }