Add cloudflare-billing skill (Cloudflare REST API, no MCP)

[dalexeenko]

Summary

Adds skills/cloudflare-billing/ — a structured investigation playbook that helps a confused Cloudflare customer make sense of their bill: outstanding balances, why they're on FREE/PRO/BUSINESS, possible double charges, pending authorizations, which zones/products drive cost.

The skill calls the Cloudflare REST API directly via curl with a scoped Account → Billing → Read token — no MCP server, no third-party dependencies. Same pattern as cloudflare-email-service.

What's included

• SKILL.md — Trigger description, prerequisites (one scoped Cloudflare token), the four REST endpoints used (with example curl invocations), a two-question-max intake, a three-step investigation order (subscriptions → billing history → reconcile), a presentation template, tone guidance, and edge cases (multi-account, deprecated history endpoint, missing per-product usage breakdown).

Endpoints used (all read-only GET)

Endpoint	Purpose
GET /accounts/{account_id}/subscriptions	Primary — full plan picture per account
GET /user/subscriptions	Fallback when user doesn't know their account ID
GET /user/billing/history?per_page=50	Charges, refunds, prorations, statuses
GET /zones/{zone_id}/subscription	Drill into one specific domain

Changes from the original PR

• Dropped the dependency on mcp-billing-server per review feedback — the skill no longer requires a non-Cloudflare MCP server.
• Dropped the Stripe tools (also non-Cloudflare).
• Removed tools.json (was the MCP server's tool schema; no longer applicable).
• Renamed the folder from billing → cloudflare-billing to match the cloudflare-<product> naming used by cloudflare-email-service.

Notes

• No changes to .mcp.json, marketplace.json, or the top-level README.md — the skill is self-contained and uses only the public Cloudflare API.
• The investigation playbook (intake → subscriptions → history → reconcile → plain-language summary) is unchanged from the original PR.

Test plan

• SKILL.md frontmatter name matches the folder (cloudflare-billing)
• Skill loads in Claude Code via the plugin marketplace install
• Auto-load trigger fires on "why was I charged" / "what plan am I on" style questions
• Investigation playbook runs end-to-end against a real account (token with Account → Billing → Read)
• Each documented curl example returns valid JSON against the live API

🤖 Generated with Claude Code