Feature Request: Allow excluding markdown files in .claude/commands from slash command discovery

Summary

Currently, every .md file placed in .claude/commands/ is automatically discovered and exposed as a slash command. There is no mechanism to exclude specific markdown files from this auto-discovery, making it difficult to co-locate documentation alongside command definitions.

Use Case

When organizing commands by feature/domain (e.g., .claude/commands/git/), it's natural to want documentation files like AGENTS.md or README.md in the same directory to provide context about those commands. However, these documentation files currently become unintended slash commands.

Current behavior:

.claude/commands/git/
├── commit.md                    → /git:commit ✅
├── commit-push.md               → /git:commit-push ✅
└── COMMANDS_GIT_AGENTS.md       → /git:COMMANDS_GIT_AGENTS ❌ (unintended)

Proposed Solutions

Any of these would solve the problem:

Option 1: Underscore Prefix Convention

Files prefixed with _ are excluded from command discovery:

.claude/commands/git/_AGENTS.md          # Ignored
.claude/commands/git/_README.md          # Ignored

Option 2: Frontmatter Option

Add a frontmatter property to exclude a file:

---
exclude-from-commands: true
---
# Documentation content here

Option 3: Configuration in settings.json

Allow specifying exclusion patterns:

{
  "commands": {
    "excludePatterns": ["**/AGENTS.md", "**/README.md", "**/_*.md"]
  }
}

Option 4: Dedicated Subdirectory

Automatically exclude a specific subdirectory name:

.claude/commands/git/
├── commit.md                    → /git:commit ✅
└── docs/                        # Entire directory excluded
    └── AGENTS.md                # Ignored

Benefits

• Keeps documentation co-located with related commands
• Follows common conventions in other CLI tools
• Reduces clutter in the slash command menu
• Enables better organization of .claude/ directory
• Supports the AGENTS.md pattern for AI context files

Current Workaround

Move documentation to .claude/docs/ or use non-.md extensions, but this separates related content and loses markdown formatting benefits.

Environment

• Claude Code CLI
• Affects all users organizing commands with documentation