nansen-mpp-payment

# MPP / Tempo The Nansen API supports three paid-access rails: API key, x402 (handled by `nansen-cli`), and MPP via Tempo (handled by the **separate** [tempo CLI](https://docs.tempo.xyz)). This skill covers the third. `nansen-cli` does **not** sign MPP credentials. Use this skill when the user wants to call the Nansen API through `tempo request` because they already use tempo, want micropayments without managing wallet keys themselves, or don't want to fund a Base/Solana USDC wallet. For API-key auth, see `nansen-wallet-manager`. For x402 micropayment with a local wallet, see `nansen-trading` / `nansen-wallet-manager`. ## When to use this skill - User says "MPP", "tempo", "Authorization: Payment", or "Payment-Receipt". - User has no Nansen API key and doesn't want to set up a Base/Solana wallet. - User is already paying for other APIs through tempo and wants Nansen on the same rail. ## One-time setup ```bash # 1. Install the tempo CLI curl -fsSL https://tempo.xyz/install | bash # 2. Log in (creates / unlocks the tempo wallet) tempo wallet login # 3. Fund it with USDC on the chain tempo selects for your environment tempo wallet fund # 4. Confirm the wallet is ready tempo wallet whoami ``` ## Calling the Nansen API `tempo request` handles the full MPP challenge/response: it sends the request, signs the `Authorization: Payment` credential when the API responds 402 + `WWW-Authenticate: Payment ...`, retries, and exposes the `Payment-Receipt` header on success. ```bash #...