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Agent402 Ox Alpha Chat Completions
x402
Agent402 Ox Alpha Chat Completions is a paid API for AI agents from agent402.tools, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-15).
Serves OpenAI-compatible chat completions using the Ox Alpha reasoning model with a 1M-token context window, payable per-call via x402 USDC or free with a trial allowance.
Price / call$0.002
Success—
StatusUnknown
How this service works
OpenAI-compatible chat completions served by Ox Alpha (stealth/ox-alpha), a reasoning model with a 1,048,576-token context window. FREE TO USE while the model's own upstream is free: add ?trial=1 and no wallet, key or signup is needed (a per-client allowance, and the response says how much is left). $0.002 per call in USDC over x402 when you want it without an allowance. The model is locked to this route (sending a different model returns a 400 naming its tier).
Output
An OpenAI-compatible chat completion response containing the assistant's message, token usage statistics (prompt, completion, reasoning tokens), and a field indicating remaining trial allowance if the trial parameter was used. The response follows the standard OpenAI ChatCompletion object format.
Example use cases
Free trial reasoning on a logic puzzle
“I want to try the Ox Alpha reasoning model for free — use the trial allowance and ask it to solve this logic puzzle with low reasoning effort: five people live in five houses, each a different color, and I need to figure out who owns the fish.”
Long-document analysis with 1M context
“Feed this entire 800-page legal contract to Ox Alpha and ask it to identify every clause that creates indemnification obligations — use high reasoning effort and a 8000 token output cap.”
Agent paying per-call via USDC x402
“Send a chat completion request to Ox Alpha via x402, paying $0.002 USDC per call, asking it to generate a detailed technical architecture for a distributed caching system — use max reasoning effort.”
Technical details
Endpoint
POSThttps://agent402.tools/v1/ox/chat/completionsWhen to prefer
Choose this endpoint when you need a powerful reasoning model accessible via the standard OpenAI chat completions API format without account signup (using the trial allowance) or with per-call USDC micropayments via x402. It is ideal for agents that need a large 1M-token context window, want to avoid subscription commitments, or are operating in a pay-per-use x402 payment flow. Prefer it over standard OpenAI or Anthropic endpoints when you want zero-signup trial access or crypto-native per-call billing.
Side effects
- 400 error if a model name other than stealth/ox-alpha is specified, naming which tier handles that model
- 402 Payment Required if trial allowance is exhausted and no x402 payment header is present
- Request rejected if reasoning effort 'none', 'minimal', or 'medium' is specified (not supported by this model)
- max_tokens below the floor of 1024 may be rejected or clamped
- Token limit exceeded if combined prompt and reasoning tokens exceed 1,048,576
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| model | string | Optional - locked to stealth/ox-alpha; any other value is a 400 naming the tier that serves it. |
| messages | array | OpenAI chat messages: [{role, content}] - text and image_url content blocks supported |
| reasoning | object | Optional - {effort: "low"|"high"|"max"}. Defaults to "low" so the budget is not spent thinking. This model always reasons; "none"/"minimal"/"medium" are not supported by it. |
| max_tokens | number | Output token cap (default 4096, floor 1024, tier maximum 8000). Reasoning tokens count against it, which is why the floor exists. |
| cache_control | — | Optional - prompt caching preference. Default ON ({type:"ephemeral"}, 5-minute TTL): repeated prefixes across your turns are served from the provider cache (same price to you). Send false to disable. ttl:"1h" is not offered. |
| max_completion_tokens | integer | Optional - alias of max_tokens (newer OpenAI SDKs send this). |
Output
Schema · Response
{
"type": "json",
"example": {
"id": "gen-…",
"model": "stealth/ox-alpha",
"usage": {
"total_tokens": 13,
"prompt_tokens": 12,
"completion_tokens": 1
},
"object": "chat.completion",
"choices": [
{
"index": 0,
"message": {
"role": "assistant",
"content": "OK"
},
"finish_reason": "stop"
}
],
"created": 1750000000
}
}Tags
x402
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