GPT-5.6 Luna is the fast, cost-efficient model in OpenAI's GPT-5.6 series — tuned for high-volume, latency-sensitive workloads while retaining genuinely capable reasoning. It is well suited to chat, classification, extraction, routing, and lightweight agentic workflows where responsiveness and price per call dominate, and still serves a full 1.05M-token context window with up to 128K output tokens. It accepts text, image, and file inputs with text output, supports configurable reasoning effort so you can dial depth up for the occasional hard request, and is a first-class OpenAI Responses model with native tool calling and structured outputs. Reach for Luna at the top of a fan-out, as a cheap first-pass or draft model, or wherever you run millions of calls and every fraction of a cent and millisecond counts.
OpenAI-compatible — keep the SDK you already use
https://api.orcarouter.ai/v1import os
from openai import OpenAI
client = OpenAI(
base_url="https://api.orcarouter.ai/v1",
api_key=os.environ["ORCAROUTER_API_KEY"],
)
response = client.chat.completions.create(
model="openai/gpt-5.6-luna",
messages=[{"role": "user", "content": "Hello"}],
)
print(response.choices[0].message.content)include_reasoningmax_completion_tokensmax_tokensreasoningreasoning_effortresponse_formatseedstructured_outputstool_choicetools| Tier | Input / 1M tokens | Output / 1M tokens | Cache read / 1M | Cache write / 1M |
|---|---|---|---|---|
| ≤ 272K | $0.200 | $1.20 | $0.020 | $0.250 |
| ≤ ∞ | $0.400 | $1.80 | $0.040 | $0.500 |
| Tier selected by input token count of each request | ||||
Estimate based on list price
Tiered pricing — this estimate uses base-tier rates.
Estimate only — actual token counts depend on the provider's tokenizer.
What developers are saying this week
GET /api/public/models/openai/gpt-5.6-lunaOpen @misc{orcarouter_gpt_5_6_luna,
title = {GPT-5.6 Luna API},
author = {OpenAI},
year = {2026},
howpublished = {OrcaRouter},
url = {https://www.orcarouter.ai/models/openai/gpt-5.6-luna}
}OpenAI. (2026). GPT-5.6 Luna API. OrcaRouter. https://www.orcarouter.ai/models/openai/gpt-5.6-luna