MCP Gateway vs APIbase

fetch

HTTP fetch with automatic authentication and payment handling. Makes the request, retries with SIGN-IN-WITH-X when the route exposes a SIWX challenge, and only pays if the route still returns 402. Returns response data and the final response headers, including raw payment receipt proof when supplied by the server, along with payment details (price, tx hash) if a payment was made. For endpoints you haven't called before in this session, you MUST call check_endpoint_schema first to confirm the request body schema. Skipping this causes 400 errors from wrong field names.

get_balance

Get your total USDC balance across all supported networks. Auto-creates the wallet on first use (~/.agentcash/wallet.json). Use this before paid API calls to confirm you have funds available.

list_accounts

List wallet accounts for each supported network. Returns the network, address, balance, and deposit link for every supported network so you can see where to fund the wallet. Auto-creates the wallet on first use (~/.agentcash/wallet.json). If onboardingCta is present, show its message to the user — it means they haven't onboarded yet and need to either visit the onboard link or deposit directly.

check_endpoint_schema

Get the input/output schema and auth mode (paid or SIWX) for a single endpoint. Call this to see exactly what fields the request body expects and what the response contains. Returns the schema from the origin's OpenAPI spec. Optionally pass sample_input_body to probe the endpoint live (without payment) for an exact price quote — do this when pricing is dynamic (range-based or variable), or when you're unsure about the input schema. Treat auth mode as advisory: fetch handles both SIWX and paid routes.

redeem_invite

Redeem an invite code for free USDC on Base. One-time use per code. Returns amount received and transaction hash. Use get_balance after to verify funds, or list_accounts if you need the per-network deposit links as well.

discover_api_endpoints

List available endpoints at an API origin. Returns endpoint URLs with descriptions of what each does and the auth mode for each (paid or SIWX). Works with any origin, not just the registered ones. Call this when you need to see what routes are available at an origin — whether it's one of the registered origins or any other origin you've identified as useful. Treat the auth mode as guidance for what the route may require; fetch handles both SIWX and payment. The response always indicates whether guidance is available. Guidance is documentation published by the API provider explaining how endpoints work together, edge cases, and usage tips. compact guidance is included automatically; set include_guidance=true to force-include full usage documentation when you need to compose two or more endpoints or need clarification on how the origin works.

report_error

EMERGENCY ONLY. Report critical MCP tool bugs. Do NOT use for normal errors (balance, network, 4xx) — those are recoverable.

update_settings

Update user settings (persisted to ~/.agentcash/settings.json). Currently supports maxAmount — the maximum USD amount allowed per fetch request. If a fetch response requests more than this, the payment is rejected. Returns the current settings after applying changes.

get_settings

Get current user settings. Returns persisted values from ~/.agentcash/settings.json with defaults applied.

bridge

Bridge USDC between supported networks using the current wallet. Requires a source network, destination network, and amount. Use this when funds are on one supported network and the user needs them moved to another. Bridging is subject to fees.

search

Search for relevant paid API services by describing what you need in natural language. Returns the best matching origins with endpoint details and pricing. The top result includes the full input/output schema so you can call it immediately via fetch. Only use this when you DON'T already know which registered origin to use. If the task clearly maps to a registered origin (e.g. people search → StableEnrich, image generation → StableStudio), skip search and go straight to discover_api_endpoints on that origin. Search is for discovering NEW or UNKNOWN capabilities outside the registered origins. Set broad=true to widen the search to include newer, unvetted tools that may not have established trust. Use this if the default results don't cover what you need.

sessions_close

Close an MPP `tempo:session` payment channel. Pass the channelId surfaced in a prior fetch's paymentInfo together with the same URL you originally fetched. Signs a close credential with the on-chain settled cumulative amount and POSTs it to the server, returning the on-chain settlement transaction hash when available. Use this when you want to finalize a channel rather than leaving it open for the server to settle on its own schedule.