# Qwen 3.8 Max Chat Completions via x402

> Qwen 3.8 Max Chat Completions via x402 is a paid API for AI agents from cursor.tail45da3a.ts.net, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).

Pay-per-call OpenAI-compatible chat completion API powered by Qwen 3.8 Max, supporting chat, reasoning, tool-calling, code generation, and summarization with 200k context — no API key required, billed at $0.005 USDC per request via x402.

## Facts

- Endpoint: POST https://cursor.tail45da3a.ts.net/x402/v2/chat/completions
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/qwen-3-8-max-chat-completions-via-x402-cb05c7f9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_C7AZ01HPzrpMSmhRIxwFz

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability qwen-3-8-max-chat-completions-via-x402-cb05c7f9 -d '<json body>'
```

Example prompt: Use the Qwen 3.8 Max chat completion endpoint (paying $0.005 USDC per call) to answer the following: given a list of customer support tickets, classify each one as 'billing', 'technical', or 'general' — here are the messages: ['My invoice is wrong', 'App keeps crashing', 'How do I reset my password?']

## When to prefer this

Choose this endpoint when you need OpenAI-compatible LLM inference without managing API keys, subscriptions, or rate-limit quotas — ideal for AI agents that can pay micropayments via x402/USDC on Base. Prefer it for sporadic or bursty inference workloads where pay-per-call is cheaper than a subscription, or when building autonomous agents that need tool-calling and long-context (200k) support. Not ideal if you need a guaranteed specific model version or if your runtime cannot handle x402 payment flows.

## Known failure modes

- Payment failure: x402 payment not provided or insufficient USDC balance — request is rejected before inference
- Model unavailable: upstream model (z-ai/glm-5.3-flash) is down or overloaded — 5xx error returned
- Invalid messages array: missing required 'role' or 'content' fields — 400 validation error
- Context length exceeded: input exceeds 200k token limit — error or truncation
- Streaming errors: SSE connection dropped mid-stream — partial response received
- Timeout: long reasoning chains may exceed connection timeouts on slow networks

## How this service works

Pay-per-call Qwen 3.8 Max LLM inference via x402 — an OpenAI-compatible chat completion API for AI agents. Flagship large language model for chat, conversation, reasoning, chain-of-thought, tool-calling / function-calling, code generation, summarization, extraction and classification, with 200k long context. No API key, signup or subscription — agents pay $0.005 USDC per request on Base.

## Output

Returns an OpenAI-compatible chat.completion JSON object containing the assistant's message content, the finish reason (e.g. 'stop'), token usage breakdown (prompt, completion, total), the model name, a completion ID, and a created timestamp. When streaming is enabled, returns Server-Sent Events with incremental completion chunks.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "model": {
   "type": "string",
   "description": "Optional; the model is served as z-ai/glm-5.3."
  },
  "tools": {
   "type": "array",
   "description": "OpenAI-compatible tool definitions for function-calling."
  },
  "stream": {
   "type": "boolean",
   "description": "If true, respond with Server-Sent Events."
  },
  "messages": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "role",
     "content"
    ],
    "properties": {
     "role": {
      "enum": [
       "system",
       "user",
       "assistant"
      ],
      "type": "string"
     },
     "content": {
      "type": "string"
     }
    }
   },
   "description": "OpenAI-compatible chat messages."
  },
  "max_tokens": {
   "type": "integer"
  },
  "temperature": {
   "type": "number"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "id": "chatcmpl-abc123",
  "model": "qwen/qwen3.8-max-free",
  "usage": {
   "total_tokens": 21,
   "prompt_tokens": 12,
   "completion_tokens": 9
  },
  "object": "chat.completion",
  "choices": [
   {
    "index": 0,
    "message": {
     "role": "assistant",
     "content": "Hello! How can I help you today?"
    },
    "finish_reason": "stop"
   }
  ],
  "created": 1767225600
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/qwen-3-8-max-chat-completions-via-x402-cb05c7f9/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from cursor.tail45da3a.ts.net](https://www.zero.xyz/host/cursor.tail45da3a.ts.net/llms.txt)