Add quiet/silent option for async hooks

+1 on this.

+1

Workaround: make your hooks output nothing to stderr when they succeed:

INPUT=$(cat)
RESULT=$(some_check 2>&1)
EXIT_CODE=$?
if [ $EXIT_CODE -ne 0 ]; then
    echo "⚠️ Hook detected issue: $RESULT" >&2
fi
exit 0

For hooks that must produce output but you want to suppress the "hook completed" notification:

exec 2>/tmp/cc-hook.log
echo "Hook ran at $(date)" >&2
exit 0

For hooks that use hookSpecificOutput (PreToolUse allow/block decisions), the JSON output goes to stdout and is consumed by the system — it doesn't produce a visible "completed" message. So the pattern is:

• Need to block/allow? → Use stdout JSON output (already silent)
• Need to warn the user? → Use stderr (shows in TUI)
• Need to log but stay silent? → Write to a file, not stderr

echo '{"hookSpecificOutput":{"hookEventName":"PreToolUse","permissionDecision":"allow"}}' 
exit 0
echo "⚠️ Warning text" >&2
exit 0

+1 — Same need here with mempalace plugin hooks (Stop and PreCompact). Memory save hooks fire on every session end and the banner/error output is pure noise for a well-tested hook. A quiet: true or silent: true field on the hook definition would be ideal.