Community Integration: AgentPay x402 — Payment middleware for AG-UI agents

## New Community Integration Submission

**Integration:** `agentpay-x402`
**Category:** Payment Middleware
**Status:** Community

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### What is it?

A drop-in middleware for AG-UI that automatically handles HTTP 402 Payment Required responses during agent tool calls — settling on Base L2 via [AgentPay](https://x402-agent-pay.com) and streaming 4 payment lifecycle events into the AG-UI event stream.

**Repository:** https://github.com/shawnhvac/ag-ui-agentpay-x402
**PyPI:** `pip install ag-ui-agentpay-x402` _(pending PyPI publish)_

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### Why it fits AG-UI

AG-UI handles the agent ↔ UI interaction layer brilliantly. The missing piece: when agents call **paid external APIs** (data, AI inference, scraping, enrichment), there's no payment primitive in the event stream. The frontend has no visibility into payments happening mid-run.

`agentpay-x402` closes that gap — no changes needed to existing agent code.

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### How it works

```python
from ag_ui_agentpay import add_agentpay_middleware

# One line — that's it
payment = add_agentpay_middleware(app, cap_usdc=5.00, chain="base")

@app.post("/agent")
async def agent_endpoint(request: Request):
async def stream():
async for event in payment.wrap(my_agent.run(body), thread_id, run_id):
yield {"data": json.dumps(event)}
return EventSourceResponse(stream())
```

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### Payment Event Types

Four new events flow into the AG-UI stream:

| Event | When | Frontend shows |
|-------|------|----------------|
| `PAYMENT_REQUIRED` | Agent hits a paid API | Amount + service name |
| `PAYMENT_PROCESSING` | Settling on Base L2 | Spinner |
| `PAYMENT_CONFIRMED` | Confirmed, agent resumes | TX hash + remaining budget |
| `PAYMENT_FAILED` | Budget exceeded / error | Error + prompt |

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### Features

- ✅ **Drop-in** — wraps any AG-UI `AsyncGenerator`, no agent changes
- ✅ **Budget guardrails** — per-run USDC cap, auto-blocks on exceed
- ✅ **Base L2 settlement** — ~2s finality, zero platform fee
- ✅ **Multi-chain** — Base, Solana, XRPL
- ✅ **ClawCredit compatible** — agents without wallets can use credit lines
- ✅ **FastAPI helpers** — `/agentpay/budget` and `/agentpay/status` endpoints
- ✅ **Full test suite** included

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### Compatible with any AG-UI framework

Works with LangGraph, CrewAI, Google ADK, Mastra, PydanticAI, and any other AG-UI-compatible agent backend — middleware is framework-agnostic.

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### x402 Service Directory

Any service returning HTTP 402 with a valid x402 header works automatically. Browse at [x402scan.com](https://x402scan.com).

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Happy to add a TypeScript implementation and demo app for the AG-UI Dojo if that would help with inclusion. Let me know what else would be useful!