| name | multiline-commit-messages |
| description | Use single-quoted strings for multiline git commit messages in the Shell tool. Prevents heredoc escaping failures that produce garbled commit messages. |
Multiline commit messages
The Shell tool sends commands as a single string. Heredoc syntax (<<'EOF') inside $(cat ...) is fragile and fails silently — the literal $(cat <<'EOF' ... ends up as the commit message instead of the intended text.
Rule
Never use $(cat <<'EOF' ...) or $(cat <<EOF ...) for commit messages.
Use single-quoted strings with embedded newlines:
git commit -m 'short summary line
Longer body paragraph explaining why the change exists.
Additional context if needed.'
Why heredocs fail
The Shell tool passes the command as a single string argument. When you write:
git commit -m "$(cat <<'EOF'
message
EOF
)"
The shell may not parse the heredoc correctly in this context — the EOF delimiter, newlines, and nested quoting interact unpredictably. The result is the raw $(cat <<'EOF' ... text appearing as the commit message.
Single-quoted strings with literal newlines are simple, portable, and always work.
