extend

ALBA Extend

Add new capabilities to the agent system. Interactive and collaborative.

Step 1: Identify

Ask: "What would you like to add to your agent?"

Types:

1. Skill - New capability (research, content creation, task automation...)
2. Hook - Automated event response (session start, error logging...)
3. Rule - Behavioral guideline (code standards, communication style...)
4. Command - Custom /slash command
5. MCP Integration - Connect external tool (Trello, Gmail, Calendar...)

Step 2: Build

Skills

1. Understand: What task? What inputs/outputs? What tools?
2. Check templates/skills/ for existing templates
3. Create .claude/skills/[name]/SKILL.md with frontmatter:

   ---
   name: [skill-name]
   description: [what it does]. Use when user says "x", "y". Do NOT use for [z].
   context: fork          # fork = subagent (protects context), inline = main context
   background: false      # fork only: wait for the result in this turn (fork defaults to background)
   allowed-tools: [tools]
   ---
   

   The description is the only field that decides whether the skill fires at the right moment — a bare one-line summary will not trigger reliably. Full field reference: templates/skills/SKILL-TEMPLATE.md.
4. Add to CLAUDE.md Skills table
5. Test immediately

Hooks

1. Identify the event. Common ones: SessionStart, UserPromptSubmit, PreToolUse, PostToolUse, PostToolUseFailure, Stop, SubagentStop, PreCompact, PostCompact, SessionEnd. Claude Code v2.1.220 defines 30 events — see templates/hooks/README-hooks.md for the full list and each one's output contract.
2. Define what should happen when triggered
3. Create .claude/hooks/[name].sh and make executable (chmod +x)
4. Add to .claude/settings.json — note the nested hooks array; skipping the inner level is the most common reason a newly added hook never runs:

   {
     "hooks": {
       "[EventType]": [
         {
           "matcher": "Bash",
           "hooks": [
             {
               "type": "command",
               "command": "${CLAUDE_PROJECT_DIR}/.claude/hooks/[name].sh",
               "timeout": 5
             }
           ]
         }
       ]
     }
   }
   

   matcher only applies to tool events. Use ${CLAUDE_PROJECT_DIR} rather than a relative path, or the hook breaks for sessions started from a subdirectory.
5. Test by triggering the event