Inspect, debug, and test Machine Payments Protocol endpoints directly from Claude Code.
MPP Inspector is a Claude Code plugin that gives you and Claude full visibility into HTTP 402 payment challenges, endpoint discovery, pricing comparison, receipt validation, and end-to-end payment flow dry-runs — all without leaving your editor.
/plugin marketplace add amgb20/mpp-inspector-marketplace
/plugin install mpp-inspector@mpp-inspector
/mpp-inspect https://mpp.dev/api/ping/paid
/mpp-scan mpp.dev
/mpp-flow https://mpp.dev/api/ping/paid
| Command | What it does |
|---|---|
/mpp-inspect <url> |
Parse and verify a 402 challenge from any URL |
/mpp-scan <domain> |
Discover MPP endpoints across a domain |
/mpp-flow <url> |
Dry-run the full payment flow step by step |
Five tools are exposed to Claude so it can reason about MPP autonomously:
| Tool | Description |
|---|---|
mpp_inspect |
Parse and verify a 402 challenge from any URL |
mpp_scan |
Discover MPP endpoints on a domain |
mpp_compare |
Compare pricing across multiple endpoints |
mpp_validate |
Verify receipts and credentials |
mpp_flow |
Dry-run the full payment flow |
A built-in skill gives Claude deep knowledge of the MPP specification — challenge parsing, payment methods (Tempo, Stripe, Lightning, Solana, Card), chain configuration, receipt and credential formats, and common debugging patterns.
Automatically detects when your project uses MPP-related code and surfaces relevant context at session start.
You can also just ask Claude:
- "Inspect the MPP challenge at https://mpp.dev/api/ping/paid"
- "Scan mpp.dev for MPP endpoints"
- "Run a dry-run payment flow against https://mpp.dev/api/ping/paid"
- "Compare pricing between these two MPP endpoints"
| Distribution | Command |
|---|---|
| CLI | npx mpp-inspector inspect https://mpp.dev/api/ping/paid |
| Global install | npm install -g mpp-inspector |
| Standalone MCP server | claude mcp add --transport stdio mpp-inspector -- npx @mpp-inspector/plugin |
- Source code & documentation: github.com/amgb20/MPP-Inspector
- NPM — CLI package: npmjs.com/package/mpp-inspector
- NPM — Plugin package: npmjs.com/package/@mpp-inspector/plugin
- MPP Protocol docs: mpp.dev/overview
Contributions are welcome! See the main repository for issues, discussions, and contribution guidelines.
MIT