External x402 client test ask: discover/fetch stable proof origin

[Bortlesboat]

Hi QuickNode team - this is an external x402 client/playground test ask, so please close if it is outside the repo scope.

I am trying to make Satoshi API discoverable to x402-aware agents and would love to know whether QuickNode's x402 client examples can discover and fetch a stable paid endpoint without custom instructions.

Stable Base Sepolia proof origin:

• https://x402.bitcoinsapi.com
• OpenAPI: https://x402.bitcoinsapi.com/openapi.json
• Well-known: https://x402.bitcoinsapi.com/.well-known/x402
• Discover: npx agentcash@latest discover https://x402.bitcoinsapi.com --format json
• Optional paid fetch: npx agentcash@latest fetch 'https://x402.bitcoinsapi.com/merchant-payout-plan?batchSize=24&targetBlocks=3&urgency=balanced'

Production mainnet surface is https://bitcoinsapi.com/x402, but the proof origin above is the safer test target.

The useful output is not a full review - just the first failure point if your examples/playground cannot discover, form the payment, settle, or parse the response.

[Bortlesboat]

Small follow-up: I tightened the external test handoff so reviewers do not have to infer command order from the catalog.

Tester kit: https://x402.bitcoinsapi.com/x402-facilitator/tester.json

It includes:

• production first paid AgentCash call: npx agentcash@latest fetch https://bitcoinsapi.com/api/v1/fees/now --payment-network base --max-amount 0.001
• no-wallet lab 402 check: curl -i https://x402.bitcoinsapi.com/weather
• lab merchant proof check: curl -i https://x402.bitcoinsapi.com/merchant-payout-plan?batchSize=24&targetBlocks=3&urgency=balanced
• MCP status: curl https://mcp.bitcoinsapi.com/status

The production first-call route is Base mainnet and returns a real Bitcoin fee snapshot; a fresh paid smoke settled tx 525bde37b90f1f20b71393e3a5a4fa3377e99d3a4baf480a0c7e6c8e73886dd2. The x402.bitcoinsapi.com routes remain Base Sepolia/native-x402 proof routes.

Public MCP is live too, and a paid MCP buyer run settled on Base Sepolia: 0x27f2db0c850823bf1e6c4f35a589106e00f39cc96a5ecf68e9a164184c3d79f1.

Current discovery state from my side: CDP search sees the proof origin; CDP resources still does not return it, so that remains a useful failure surface to confirm or explain.

If you try one thing, the most useful reply is just one label plus first failure: discovery_ok, 402_metadata_mismatch, paid_fetch_failed, paid_fetch_succeeded, or outside_scope.

[afurm]

I tested the links from this issue:

• npx agentcash@latest discover https://x402.bitcoinsapi.com --format json succeeds and discovers /weather and /merchant-payout-plan.
• Raw unauthenticated requests to the paid routes return 402 with a PAYMENT-REQUIRED header on eip155:84532.
• The package can already complete the normal x402 retry flow once a paid resource URL is known.

The gap I found is discovery ergonomics: @quicknode/x402 did not expose a package-level helper to turn an origin into a list of paid resources.

I opened a fix that adds discoverX402Origin(), which reads /.well-known/x402 first and falls back to /openapi.json payment metadata. I also smoke-tested it against https://x402.bitcoinsapi.com, and it returns:

• GET /merchant-payout-plan at $0.003
• GET /weather at $0.001
• network eip155:84532

[Bortlesboat]

Thanks, this is exactly the gap I was hoping this issue would surface.

I rechecked the seller-side discovery inputs just now:

• /.well-known/x402 is live and advertises /merchant-payout-plan and /weather on Base Sepolia eip155:84532
• raw /weather still returns 402 plus the payment-required header

So from my side I’d mark the current state as discovery_ok: the proof origin is discoverable, and #13 looks like the right package-level ergonomics fix for QuickNode consumers. Once #13 lands or is otherwise installable, I’m happy to run the helper against the proof origin again and report the exact output.

Thanks for testing this and turning the issue into an actionable API.