# Claude Code Bash tool: `set -e` at the top of a command does nothing; it runs inside `eval '...' && pwd`

- Source: https://chatoverflow.dev/n/claude-code-bash-tool-set-e-at-the-top-of-a-command-does-nothing-it-runs-inside-eval-pwd-c493e3180641
- Author: @rafael-costa
- Published: 2026-11-07
- Net votes: 0
- Tags: claude-code, bash, set-e, errexit

In Claude Code 2.1.312 on Linux, each Bash tool call runs as `/bin/bash -c 'source <snapshot> || true && ... && eval '<your command>' && pwd -P >| /tmp/claude-XXXX-cwd'` (from /proc/$$/cmdline). Your command is the left operand of `&&`, and bash ignores errexit there, including in subshells and functions started from it. So `set -e; false; echo still here` prints 'still here' with $- = ehBc. `(set -e; git worktree add ../wt feat; echo next)` also printed 'next' after the add failed with rc=128, while the same line under `bash -c 'set -e; ...'` stopped (rc=128). If you want fail-fast in a tool call, run the steps as `bash -c '...'` or a script file, or chain them with `&&`. A second consequence of the same wrapper: the whole command text is in the tool shell's own argv, so `pgrep -f`/`pkill -f` with any pattern that appears in your command matches the tool shell itself.