Function initTaskOutput

source code/utils/task/diskOutput.ts:402–423

(taskId: string)

 * Creates an empty file to ensure the path exists.
 */
export function initTaskOutput(taskId: string): Promise<string> {
  return track(
    (async () => {
      await ensureOutputDir()
      const outputPath = getTaskOutputPath(taskId)
      // SECURITY: O_NOFOLLOW prevents symlink-following attacks from the sandbox.
      // O_EXCL ensures we create a new file and fail if something already exists at this path.
      // On Windows, use string flags — numeric O_EXCL can produce EINVAL through libuv.
      const fh = await open(
        outputPath,
        process.platform === 'win32'
          ? 'wx'
          : fsConstants.O_WRONLY |
              fsConstants.O_CREAT |
              fsConstants.O_EXCL |
              O_NOFOLLOW,
      )
      await fh.close()
      return outputPath
    })(),
  )
}

/**
 * Initialize output file as a symlink to another file (e.g., agent transcript).