feat: add moonpay-mpp skill

[kevarifin14]

Summary

• Adds moonpay-mpp skill for making paid API requests to MPP (Machine Payments Protocol) protected endpoints
• Uses Tempo stablecoins for automatic HTTP 402 payment handling
• Mirrors the existing moonpay-x402 skill pattern

What is MPP?

MPP is the open standard for machine-to-machine payments via HTTP 402, co-developed by Tempo and Stripe. It's backwards-compatible with x402 but adds Stripe cards, Tempo stablecoins, Lightning, and sessions.

Usage

mp mpp request --method GET --url https://some-mpp-endpoint.com/api --wallet default

🤖 Generated with Claude Code

[kevarifin14]

Review: moonpay-mpp skill — Grade: D (Significant rework needed)

Blocking issues

1. mp mpp request does not exist (automatic rejection territory)

The core command this skill is built on — mp mpp request — does not exist in the MoonPay CLI. Verified against @moonpay/cli@1.12.4 (latest):

$ mp mpp --help
# Falls through to top-level help — no "mpp" subcommand listed

The CLI has x402 but no mpp subcommand. The entire skill instructs agents to use a fabricated command. Per the rubric: "Every CLI command and API endpoint in the skill must be verifiable and functional. Hallucinated or fabricated commands are an automatic rejection."

If mp mpp is planned but not yet shipped, the skill should not be submitted until the command is live and verifiable.

2. Missing marketplace.json update

The diff only adds skills/moonpay-mpp/SKILL.md. There is no corresponding update to .claude-plugin/marketplace.json. Since this is a MoonPay first-party skill (moonpay-mpp), it needs to be added to the moonpay-skills plugin block.

3. Missing Prerequisites section

The template requires a Prerequisites section listing setup requirements (CLI install, auth, funded wallet). This skill has no Prerequisites section. It mentions "Use moonpay-auth to set up a local wallet first" buried in Notes, but that's not a substitute for a proper Prerequisites block.

Non-blocking issues

• Description could be more trigger-specific. Current: "Make paid API requests to MPP-protected endpoints using Tempo stablecoins." Better: "Use when the user wants to call an API that requires MPP (Machine Payments Protocol) payment — detects HTTP 402 responses and pays automatically with Tempo stablecoins."
• No Error Handling section. The template includes one; common errors like insufficient balance, wallet not found, or non-402 endpoints would be useful.
• No Workflow section. The "Example flow" is close but the template expects a numbered Workflow section with unambiguous executable steps.
• MPP/Tempo claims are unverifiable. "MPP is the open standard for machine-to-machine payments via HTTP 402, co-developed by Tempo and Stripe" — I cannot independently verify this claim. A link to documentation would strengthen the skill.

What's good

• Naming convention (skills/moonpay-mpp/) is correct for a MoonPay first-party skill.
• Frontmatter has name, description, and tags.
• Cross-referenced skills (moonpay-auth, moonpay-check-wallet, moonpay-x402, moonpay-upgrade) all exist in the repo.
• No code — purely instructional. Clean diff with no unrelated changes.
• No security concerns with private key handling.

Required before re-review

1. Ship mp mpp request in the CLI first, or change the skill to use whatever real command handles MPP. This is non-negotiable.
2. Add the skill to marketplace.json in the moonpay-skills plugin block.
3. Add a Prerequisites section.
4. Add an Error Handling section.
5. Restructure to match the template more closely (Overview, Prerequisites, Commands, Workflow, Examples, Error Handling, Related Skills).