Closes#2983.
Allow exec_shell to opt into the existing parallel tool lane when its concrete input is a conservative read-only shell command. The whitelist covers direct git/list/search/read commands plus simple bash/sh/zsh -c wrappers whose inner command passes the same classifier; anything effectful, interactive, redirected, piped, backgrounded, or stdin-fed remains serial and approval-gated.
Parallel exec_shell fanout is capped at four workers, and explicit multi_tool_use.parallel now preserves request-order results while using the same input-aware checks.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Hunter B
f8b3c1e481