skillkit

Local-first analytics for AI agent skills. Track usage, measure context budget, and prune what you don't use.

npx @crafter/skillkit stats

Auto-discovers your skills, indexes sessions, and shows what matters. No setup needed.

Why

AI coding agents load skills into their context window on every session. More skills = less room for your actual code. But which skills do you actually use? Which ones are wasting context budget?

skillkit answers these questions by scanning your session files, tracking invocations, and surfacing actionable insights - all locally on your machine.

Commands

Command	Description
`stats`	Usage analytics with sparklines (auto-scans on first run)
`list`	List installed skills with size and context budget
`health`	Health check: unused skills, context budget, DB
`prune`	Remove unused skills to reclaim context budget
`context`	Context tax: tokens and cost loaded on every API call
`burn`	Token burn rate and cost across agents
`scan`	Force re-scan (runs automatically, rarely needed)

Flags

Flag	Applies to	Description
`--mcp`	context	Measure MCP server tool schemas (spawns each server)
`--compare <name>`	context	Diff against a saved baseline
`--save-baseline <name>`	context	Save the current measurement
`--days N`	stats	Time range in days (default: 30)
`--all`	stats	Show all skills, not just top 10
`--include-commands`	scan	Also track slash commands
`--claude`	any	Only scan Claude Code
`--opencode`	any	Only scan OpenCode

Install skills via skills.sh: npx skills add <owner/repo>

Use as a Skill

Install skillkit as a skill so the agent can run analytics commands for you:

npx skills add crafter-station/skills --skill skillkit

Then ask your agent things like "which skills do I use the most?" or "clean up unused skills" and it will run the right commands.

How It Works

Stats

Auto-discovers skills on first run, parses session data from supported connectors, and shows sparkline trends.

$ npx @crafter/skillkit stats
  First run detected, scanning skills...
  Found 12 skills.

  SKILL-KIT ANALYTICS (last 30 days)

  Total invocations: 419
  Unique skills:     66
  Most active day:   Monday

  TOP SKILLS

  react-best-practices  ████████████████████   109  ▁▅▂▁▂▂█▅▁▂
  agent-browser         ██████████              56  ▂█▇▃▁▁▁▂▁▁▃▂▂▃▂
  pulse                 ██████                  32  ▁▁█▁▁▁▁▁

Health

Checks context budget usage and flags unused skills.

$ npx @crafter/skillkit health
  [████████░░] 78% metadata budget (12.5K / 16.0K)
  ! 3 skills unused in 30d - run skillkit prune

Prune

Removes skills that haven't been used in the last 30 days.

$ npx @crafter/skillkit prune
  x scaffold (0.9K)
  x lint (2.1K)

  2 skills - 3.0K context reclaimable

  Run with --yes to confirm deletion.

Data Storage

All data stays on your machine. Analytics live in ~/.skillkit/analytics.db; every agent source below is read-only.

Supported Agents

Session connectors (skill invocations tracked from local session data):

Agent	Format	Session source
Claude Code	JSONL	`~/.claude/projects/*/.jsonl`
OpenCode	SQLite	`opencode.db` (XDG data dir)
Cursor	JSONL	`~/.cursor/projects/*/.jsonl`
Codex	JSONL	`~/.codex/sessions/*/.jsonl`
Gemini CLI	JSON	`~/.gemini/tmp/*/chats/session-.json`
Amp	JSON	`$XDG_DATA_HOME/amp/threads/*.json` (legacy; modern Amp stores threads server-side)
Cline	JSON	VS Code `globalStorage/saoudrizwan.claude-dev/tasks` + `~/.cline/data/tasks`
Roo Code	JSON	VS Code `globalStorage/RooVeterinaryInc.roo-cline/tasks`
Kilo Code	SQLite + JSON	`kilo.db` (XDG data dir) + legacy globalStorage tasks
Continue	JSON	`~/.continue/sessions/*.json`
Goose	SQLite + JSONL	`sessions.db` (XDG data dir) + legacy `*.jsonl`
GitHub Copilot CLI	JSONL	`~/.copilot/session-state/*/events.jsonl`
OpenHands	JSON	`~/.openhands/{conversations,v1_conversations}`
Windsurf	SQLite	`state.vscdb` (Windsurf globalStorage)

Filter any command by agent, e.g. --claude, --opencode, --cursor.

Not trackable yet: Trae (closed-source, no documented local conversation storage). Windsurf's native Cascade trajectories (~/.codeium/windsurf/cascade/*.pb) are encrypted at rest; the connector reads the VS Code state database instead.

Skill discovery (which skills are installed where) covers all 75 agents in the skills.sh ecosystem via a vendored registry (agent-registry.generated.json, re-synced with bun run scripts/sync-agent-registry.ts).

Adding a connector

Each agent is an isometric adapter implementing the Connector interface (packages/cli/src/scanner/connector.ts): count(), scan(), plus a parse* function tested against fixtures faithful to the agent's real session schema. Register it in packages/cli/src/scanner/registry.ts - no other wiring needed.

Project Structure

skill-kit/
├── apps/web/          # Landing page (Next.js)
├── packages/cli/      # CLI tool (Bun, zero deps)
└── packages/skill/    # Skill definition (SKILL.md)

Development

bun install

# Run CLI locally
bun run packages/cli/src/bin.ts stats

# Run landing page
bun run --filter '@crafter/skillkit-web' dev

# Type check
bun run --filter '*' type-check

# Lint
biome check --write .

License

MIT