d20 System Initialization

Initialize d20 system mechanics in the current adventure directory by merging GM guidance into CLAUDE.md.

Instructions

Perform the following steps to initialize the d20 system:

Step 1: Merge d20-CLAUDE.md into CLAUDE.md

The d20-CLAUDE.md file contains complete d20 GM guidance including quick reference tables for all core mechanics. It must be appended to the project's CLAUDE.md file.

1. Read ${CLAUDE_PLUGIN_ROOT}/d20-CLAUDE.md
2. Check if ./CLAUDE.md exists in the current directory:
   • If it exists, read its contents
   • If it does not exist, start with empty contents
3. Idempotency check: Search the existing CLAUDE.md content for the marker # d20 System GM Guidance
   • If the marker is found, the d20 guidance has already been merged - skip to Step 2
   • If the marker is NOT found, append the d20-CLAUDE.md content to the end of CLAUDE.md
4. Write the updated CLAUDE.md to ./CLAUDE.md

Important: When appending, preserve all existing CLAUDE.md content exactly as-is. Add a blank line before the new content for separation.

Step 2: Report Success

After completing, report the results:

d20-system initialized!

Files updated:
- CLAUDE.md (GM guidance and quick reference appended)

Next steps:
1. Create player.md using the d20-players skill
2. Start your adventure!

For detailed mechanics, invoke the appropriate skill:
- d20-players: Character creation and advancement
- d20-combat: Combat and initiative
- d20-magic: Spellcasting mechanics
- d20-rules: Authoritative SRD rule lookups

If the d20-CLAUDE.md content was already present (idempotency check triggered), report:

d20-system already initialized!

CLAUDE.md already contains d20 GM guidance - no changes made.

Ready to play! Use d20-players to create a character or d20-rules for rule lookups.

Error Handling

If any file operations fail, report the specific error and which step failed. The user may need to check permissions or the plugin installation.

Notes

• This command is idempotent: running it multiple times will not duplicate content in CLAUDE.md
• All d20 mechanics are now in CLAUDE.md - no separate System.md file needed
• For detailed mechanics during play, invoke the appropriate skill (d20-players, d20-combat, d20-magic, d20-rules)