# CarsonBot402

Carson Roscoe works on CDP at Coinbase and helped incubate x402 in its early days. CarsonBot402 is his bot: GitHub maintenance for x402-foundation/x402, plus x402 Q&A with citations and a scheme visualizer on this site.

## When to use CarsonBot402

Use CarsonBot402 when you need **grounded x402 protocol help** with citations—not generic LLM guesses.

- **Debugging x402**: HTTP 402, PAYMENT-REQUIRED headers, facilitator verify/settle failures on Base or Solana, Bazaar discovery metadata, and SDK wiring (`@x402/core`, `@x402/next`, `@x402/fetch`, MCP buyers).
- **Building sellers**: Next.js/Express/Hono paid routes, `declareDiscoveryExtension`, OpenAPI + `/.well-known/x402`, DNS `_x402` TXT, and CDP Facilitator validation.
- **Learning**: scheme visualizer traces and curated Learn guides on this site.

**Do not use** CarsonBot402 for unrelated crypto trading advice, non-x402 payments, or tasks that need live chain execution without a wallet.

## Agent discovery

- [OpenAPI (carsonbot402)](https://www.carsonbot402.dev/openapi.json)
- [x402 well-known manifest](https://www.carsonbot402.dev/.well-known/x402)
- [RFC 9727 API catalog](https://www.carsonbot402.dev/.well-known/api-catalog)
- [llms.txt (this file)](https://www.carsonbot402.dev/llms.txt)
- [robots.txt with Content Signals](https://www.carsonbot402.dev/robots.txt)

## Paid HTTP APIs (x402)

- [POST https://www.carsonbot402.dev/api/ask](https://www.carsonbot402.dev/api/ask): $0.01 exact USDC on Base or Solana mainnet, settled through CDP Facilitator and discoverable in CDP Bazaar. x402 debugging/troubleshooting Q&A: Ask any question, get a cited answer. Whether you need HTTP 402 Payment Required help, facilitator verify & settle (CDP @coinbase/cdp-sdk), Bazaar discovery metadata & listing, protocol documentation, Next.js paid routes, or planning, building, and integrating x402 servers: @x402/core @x402/next @x402/express @x402/hono @x402/fastify @x402/fetch @x402/axios @x402/mcp; Gin; FastAPI/Flask. Base & Solana USDC.

## Repo CLI (coding agents)

Clone this repo, set secret `ASK_X402_PAYER_EVM_KEY` (Base USDC), then run:

```bash
pnpm ask-carsonbot402 -- "Your x402 question?"
```

See `.cursor/skills/ask-carsonbot402/SKILL.md` and `AGENTS.md`. Dry-run 402 metadata: `pnpm ask-carsonbot402 -- --dry-run "…"`.

## MCP (Streamable HTTP)

- [https://www.carsonbot402.dev/mcp/connect](https://www.carsonbot402.dev/mcp/connect): Streamable HTTP MCP server with x402-paid ask_anything_x402 and raw HTTP ask_anything_x402_raw tools.
- MCP x402 client docs: https://docs.cdp.coinbase.com/x402/buyer/mcp-payments

## Learn and reference

- [Learn schemes](https://www.carsonbot402.dev/learn/schemes)
- [Ask (isolated paid questions)](https://www.carsonbot402.dev/ask)
- [About](https://www.carsonbot402.dev/about)
- [x402 repo](https://github.com/x402-foundation/x402)
- [x402 docs](https://docs.x402.org)
- [x402scan discovery spec](https://www.x402scan.com/discovery/spec.md)

## Human follow-ups after deploy

- Run CDP facilitator validate on production keys.
- Settle a real USDC payment against POST /api/ask.
- Register the origin on x402scan and Circle merchant flows when ready.
- Listing playbook: docs/listing-strategy.md in the CarsonBot402 repo.
- Publish DNS TXT at _x402 (see docs/agent-discovery.md on the repo).