Function getSimpleCommandPrefix

src/tools/BashTool/bashPermissions.ts:162–189

(command: string)

 *   'chmod 755 file' → null (number, not a subcommand)
 */
export function getSimpleCommandPrefix(command: string): string | null {
  const tokens = command.trim().split(/\s+/).filter(Boolean)
  if (tokens.length === 0) return null

  // Skip env var assignments (VAR=value) at the start, but only if they are
  // in SAFE_ENV_VARS (or ANT_ONLY_SAFE_ENV_VARS for ant users). If a non-safe
  // env var is encountered, return null to fall back to exact match. This
  // prevents generating prefix rules like Bash(npm run:*) that can never match
  // at allow-rule check time, because stripSafeWrappers only strips safe vars.
  let i = 0
  while (i < tokens.length && ENV_VAR_ASSIGN_RE.test(tokens[i]!)) {
    const varName = tokens[i]!.split('=')[0]!
    const isAntOnlySafe =
      isInternalBuild() && ANT_ONLY_SAFE_ENV_VARS.has(varName)
    if (!SAFE_ENV_VARS.has(varName) && !isAntOnlySafe) {
      return null
    }
    i++
  }

  const remaining = tokens.slice(i)
  if (remaining.length < 2) return null
  const subcmd = remaining[1]!
  // Second token must look like a subcommand (e.g., "commit", "run", "compose"),
  // not a flag (-rf), filename (file.txt), path (/tmp), URL, or number (755).
  if (!/^[a-z][a-z0-9]*(-[a-z0-9]+)*$/.test(subcmd)) return null
  return remaining.slice(0, 2).join(' ')
}

// Bare-prefix suggestions like `bash:*` or `sh:*` would allow arbitrary code
// via `-c`. Wrapper suggestions like `env:*` or `sudo:*` would do the same: