# Build mppx Payment Authentication Flows

402 Payment Required integrations need careful client, server, wallet, and secret handling. This skill guides mppx setup for Tempo, Stripe, MCP, and framework middleware.

## Install

```bash
npx skillstore add internet-court/mppx
```

## Metadata

- Status: approved
- Slug: internet-court-mppx
- Skillstore revision: r1
- Version status: missing
- Tree hash: 265d2da796c08b4fb4df90a377c7eef0b91d8d50316a9f26a8fc6cec29160e83
- Author: internet-court
- GitHub username: internet-court
- License: MIT
- Repository: https://github.com/internet-court/internet-court-skill/tree/main/vendored/tempo/mppx
- Ref: 3f6e026a3363e0954ede7bef0cfe88d4475de137
- Supported tools: Claude, Codex, Claude Code
- Audit status: complete
- Agent install advisory: allowed
- Manual install advisory: allowed
- Artifact signature: available
- Audit attestation: unavailable
- Human verification: not\_verified
- Risk factors: external\_commands, network, env\_access
- Quality score: 69
- Public page: https://skillstore.pages.dev/skills/internet-court-mppx
- Manifest: https://skillstore.pages.dev/api/skills/internet-court-mppx/manifest

## Capabilities

- Shows client 402 handling with global fetch or explicit mppx fetch calls.
- Explains server challenge and receipt flows for protected HTTP routes.
- Lists Tempo and Stripe methods for charge and session payment flows.
- Identifies exports for core, client, server, and framework middleware packages.
- Provides development CLI examples for wallet creation and paid requests.

## Use Cases

- Add Paid API Client Calls: Integrate mppx client handling so a TypeScript app can respond to 402 challenges.
- Protect Server Routes: Design a server route that issues challenges, verifies credentials, and returns receipts.
- Plan Paid MCP Tools: Wrap MCP clients or servers so selected tool calls can require payment.

## Prompt Templates

### Add Client Handling

```
Use the mppx skill to add client-side 402 handling for an existing TypeScript fetch call. Keep secrets out of browser code.
```

### Protect a Route

```
Use the mppx skill to protect a server route with Tempo charge payments. Include required inputs and security checks.
```

### Choose a Method

```
Use the mppx skill to compare tempo.charge, tempo.session, and stripe.charge for this product: [describe product].
```

### Design Paid MCP Flow

```
Use the mppx skill to design a paid MCP client and server flow. Include confirmation points before wallet or payment actions.
```

## Limitations

- It is documentation guidance, not a runnable payment service.
- Examples use placeholder endpoints, keys, addresses, and response data.
- Stripe and Tempo examples require separately configured accounts and wallets.
- It does not validate live payment terms, chain state, or receipts.

## Best Practices

- Keep MPP\_SECRET\_KEY and wallet private keys only on trusted server systems.
- Verify runtime 402 challenges before signing credentials or sending payments.
- Confirm amount, currency, recipient, and network before any paid request.

## Anti Patterns

- Do not paste real wallet private keys into prompts or source examples.
- Do not expose server secret keys to browser code or logs.
- Do not run paid CLI commands without explicit user approval.

## Security Audit

- Audited at: 2026-07-21T03:24:25.221\+00:00
- Summary: Most static findings are Markdown, placeholder, or documentation matches and are false positives. The two request examples intentionally contact a user-selected endpoint and can handle payment challenges. The documented CLI can create wallets and issue paid requests, so payment actions require explicit user review.

## Stats

- Views: 1
- Downloads: 4
- Favorites: 1
- Popularity score: 0