claude-starter
An opinionated Claude Code skill pack for fintech devs and Anthropic power-users. Six deep, handwritten skills plus a thin CLI for TOON — a JSON compression format that typically cuts input tokens 40–60% on tabular data.
No orchestration framework. No aspirational YAML. Just skills that activate when you need them.
What you get
6 top-level skills — auto-activate on keywords:
| Skill | Covers |
|---|
| stripe | Checkout, Payment Intents, subscriptions, Connect/marketplace, Terminal, Radar, Treasury, Issuing, webhooks (signature + idempotency) — 2,100+ lines of real patterns |
| supabase | Postgres + RLS, Auth (OAuth + SSR cookies), Realtime, Storage, Edge Functions, pgvector |
| plaid | Link flow, Auth (ACH routing/account numbers), Transactions sync, Identity (KYC), Accounts + balance |
| expo | EAS Build (eas.json, credentials, CI), EAS Update (OTA, channels, staged rollouts), Expo Router (file-based routing, dynamic segments, layout groups) |
| anthropic | Anthropic Claude API — Messages API, prompt caching, tool use, vision, model migration. Includes 6 Claude Code meta-tooling sub-skills: skill-builder, command-builder, hook-builder, mcp-expert, settings-expert, claude-code |
| toon-formatter | When TOON helps, when it doesn't, how to wire the commands |
5 slash commands for TOON:
/convert-to-toon <file> — encode + report measured savings/analyze-tokens <file> — compare JSON vs TOON token counts without writing a file/toon-encode <file>, /toon-decode <file>, /toon-validate <file>
All TOON commands shell out to the canonical @toon-format/toon npm library via a 90-line wrapper at .claude/utils/toon/cli.mjs, and use gpt-tokenizer for real token counts (OpenAI BPE — directionally accurate proxy for Claude; for exact counts use Anthropic's /v1/messages/count_tokens endpoint).
Install
# Into current project
npx create-claude-starter@latest
# Into a specific dir, no prompts
npx create-claude-starter@latest ./my-app --yes
For TOON commands, add the runtime deps to your project:
npm i @toon-format/toon gpt-tokenizer
Use
Skills auto-activate on context:
User: How do I verify a Stripe webhook signature?
Claude: [stripe-expert activates] Use stripe.webhooks.constructEvent...
User: Convert api-response.json to TOON
Claude: [runs /convert-to-toon api-response.json]
✓ Wrote api-response.toon
Tokenizer: gpt-tokenizer (OpenAI BPE — approximate proxy for Claude)
JSON: 4,587 tokens (12,840 bytes)
TOON: 2,759 tokens (7,128 bytes)
Saved: 1,828 tokens (39.8%)
Why this exists
The Claude Code skill market is fragmented: Anthropic ships 17 general-purpose skills and nothing for fintech or platform integrations. Community mega-packs (awesome-claude-code-toolkit, antigravity-awesome-skills) compete on volume — 1,400+ skills with razor-thin depth.
This pack goes the other way: 6 skills, hand-maintained, each genuinely better than what's out there. The Stripe skill alone is 2,100+ lines of tested integration patterns. If you're building a fintech app or extending Claude itself, this is the starting point.
Not in this repo (and why)
- Orchestration / semantic matching / multi-skill workflows — removed. Claude Code selects skills natively via frontmatter
description; the previous TypeScript orchestration engine was placeholder code.
- YAML workflow engine — removed. Out of scope for a skill pack.
- Meta-commands / command registry / validators — removed. Claude Code's built-in
/skill and plugin system handle this.
- Native Zig TOON binary — removed. The canonical
@toon-format/toon npm package (1.8M downloads/month) ships pure JS, cross-platform.
- Blockchain / iOS / Shopify / Whop skills — removed. Niche or thin; if you need them, spin a focused pack.
- Duplicated code-quality skills — removed. Anthropic already ships
cleanup-unused, cleanup-slop, etc. natively.
Structure