Feature: Deferred skill loading (like deferred tools)

Problem

Skill descriptions are injected into every system prompt message, consuming significant context tokens. With 60+ skills installed (from plugins like everything-claude-code, superpowers, cloudflare, etc.), this adds ~15-20k tokens of skill descriptions repeated in every turn's system reminder.

This is in contrast to deferred tools, which only inject their name into a lightweight index and load full schemas on demand via ToolSearch. Skills have no equivalent lazy-loading mechanism.

Impact

• Heavy plugin users (20+ plugins, 60+ skills) lose meaningful context to skill description overhead
• Skills for irrelevant languages/frameworks (Django, Spring Boot, Perl) inject into every session regardless of project type
• No project-level skill scoping — all skills load everywhere
• The only workaround is physically deleting skill files from the plugin cache (fragile, lost on update)

Proposed Solution

Deferred skill loading — same pattern already built for tools:

1. Lightweight index: Inject only skill name + one-line trigger pattern into the system prompt (like deferred tools show only names)
2. On-demand loading: Full skill content loaded via Skill tool only when matched/invoked
3. Optional: Per-project skill allowlist in .claude/settings.json to scope which skills are active

This would also enable:

• Plugin authors to ship large skill libraries without context tax
• Users to install broad plugins (ECC, superpowers) without paying for unused skills
• Better scaling as the plugin ecosystem grows

Current Workarounds

• Disabling entire plugins (loses hooks/agents/MCP servers bundled with skills)
• Deleting skill files from ~/.claude/plugins/cache/ (lost on plugin update)
• No per-skill or per-category disable mechanism exists

Context

Discovered during a context optimization session where the skill description list itself was a primary contributor to context consumption. The irony was not lost on us.

Environment

• Claude Code CLI
• Opus 1M context plan
• 22 plugins, 62 skills, 44 agents, 35 hooks, 13 MCP servers