Custom slash commands in Claude Code: how they work now that commands are skills

You type /fix-issue 123 and Claude Code expands it into a full prompt with your team's standards attached. Custom slash commands are the cheapest automation in Claude Code — one markdown file, zero config — and they changed in a way that's easy to miss: custom commands have been merged into skills. Your .claude/commands/ files keep working, but the merged model explains several things that look like bugs (arguments not expanding, tool grants vanishing mid-task) and adds features commands never had.

Here is the current behavior, verified against the official docs as of late July 2026.

The one-file version still works

Drop a markdown file into your project:

<!-- .claude/commands/fix-issue.md -->