[BUG] Slash commands not loading in version 2.0.27 - "Unknown slash command" error

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Bug Report:

## Environment

• Claude Code Version: 2.0.27
• Platform: Linux (WSL2)
• OS Version: Linux 6.6.87.1-microsoft-standard-WSL2
• Commands Directory: /home/jrg/.claude/commands/

## Description
Slash commands are not being discovered or registered by Claude Code. Commands exist in the
correct directory with proper frontmatter formatting, but invoking them results in "Unknown slash
command" errors.

Additional Context

• This appears to be a regression - slash commands worked in previous versions
• The SlashCommand tool exists and is available, but command discovery/registration is failing
• Commands are never listed in available commands
• No errors shown during startup about command loading failures

Impact

Users cannot utilize custom slash commands, forcing manual copy-paste of command templates or
workarounds using MCP servers/plugins instead.

What Should Happen?

## Expected Behavior
The slash commands should be recognized and executed, expanding the prompt content from the
markdown files.

## Actual Behavior
Error returned:
Error: Unknown slash command: wrap-up

Error Messages/Logs

## Evidence
  Commands exist and are properly formatted:
  
  $ ls -la ~/.claude/commands/
  total 24
  drwxr-xr-x  2 jrg jrg 4096 Oct  5 09:00 .
  drwxr-xr-x 13 jrg jrg 4096 Oct 24 21:55 ..
  -rw-r--r--  1 jrg jrg 6306 Oct  5 09:00 audit.md
  -rw-r--r--  1 jrg jrg 5186 Oct  5 09:00 wrap-up.md

  Example command frontmatter from wrap-up.md:
  ---
  description: "Generate comprehensive project wrap-up documentation with findings, decisions, and     
  next steps"
  argument-hint: "[optional: specific focus like 'findings', 'technical', 'decisions',
  'next-steps']"
  ---

Steps to Reproduce

## Steps to Reproduce

1. Create slash command files in ~/.claude/commands/:

• audit.md with proper frontmatter (description, argument-hint)
• wrap-up.md with proper frontmatter

1. Start Claude Code
2. Attempt to invoke command with /wrap-up or /audit

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.0.27

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

WSL (Windows Subsystem for Linux)

Additional Information

This happens intermittently that it stops working - perhaps with new versions - not necessarily new with this version