list_market_apis, pays per call from a single Sella wallet, and never manages a single upstream API key or vendor signup. Discovery is over MCP; execution flows through a dedicated AgentWallet that proxies paid calls using x402 or MPP.
The AgentWallet is a separate onboarding step from your core agent authentication, purpose-built for pay-per-call API proxying. It stores its configuration at
~/.sella-agentwallet/config.json and provisions wallets on Base, Solana, Ethereum, and Tempo.Onboard the AgentWallet
Complete this onboarding once per agent environment. If~/.sella-agentwallet/config.json already contains username, apiToken, and apiBase, skip to the safe call flow below.
1
Check for existing config
Inspect
~/.sella-agentwallet/config.json. If it contains username, apiToken, and apiBase, your AgentWallet is already provisioned and you can proceed directly to making calls.2
Start the connection
Send your email address to the connect endpoint. Sella will dispatch a one-time passcode (OTP) to that address.
3
Complete with the OTP
Submit your email, chosen username, and the OTP you received. The response contains your Save the returned object to
apiToken and wallet addresses.~/.sella-agentwallet/config.json with owner-only file permissions (chmod 600). Never log or print the apiToken after saving it — treat it as a secret credential.4
Fund your wallet
Open the
fundingUrl from the config response to deposit USDC. If a paid API call later returns WALLET_UNFUNDED, forward that URL to the human operator and retry once they have topped up the balance.The safe call flow
The AgentWallet proxy is built around a dry-run first, explicit approval second pattern. Your agent must never spend from the operator’s wallet without an explicit sign-off. Follow these steps on every API call.Search
Discover candidates with Filter by
list_market_apis over MCP, or query the market backend directly:domain_type, product_class, chain, verified_only, and max_price_usdc to narrow the list before inspecting individual endpoints.Inspect
Load the full endpoint record and its generated usage instructions:Read the skill document carefully — it describes the required inputs, expected output shape, and any provider-specific constraints.
Dry-run
Call the proxy with
dryRun: true to validate your inputs and receive the policy, required fields, and an estimated price — without spending any funds.Summarize and get approval
Present the following to the human operator and wait for explicit approval before proceeding:
- Endpoint name and what it does
- The inputs you plan to send
- Estimated price in USDC
- Settlement chain
- Data source and any known risks
Execute
Repeat the request with
dryRun: false and approved: true. Route through the appropriate proxy action based on the provider’s payment protocol:- x402 providers:
POST /api/wallets/{username}/actions/x402/fetch - MPP / Tempo providers:
POST /api/wallets/{username}/actions/mpp/pay
Authorization: Bearer <apiToken> on all wallet and proxy requests.Prices and chains
The runtime402 challenge (or MPP equivalent) is the authoritative source for the exact price and settlement chain on every call. Endpoint metadata carries estimates only — do not hard-code prices. Most providers settle on Base or Solana; Tempo is used for MPP-style flows.
Discover APIs
Filter 1,400+ providers by domain type, product class, chain, and price cap before you inspect or call any endpoint.
x402 and MPP reference
Understand how per-call payment settlement works under the hood — challenges, signatures, and facilitator flow.