GPT-5.6 Luna
GPT-5.6 Luna is in limited preview with a tracked OpenAI API route; evaluate it only if you have access, and wait for broader availability plus fuller context and benchmark evidence before migrating production.
Use it for
- Teams that already qualify for GPT-5.6 Luna's limited preview
- Teams evaluating the sourced OpenAI API route
- Architecture watchlists waiting for broad availability
Do not use it for
- Production launches that need broad self-serve access
- Migrations that require confirmed context and output limits
- Benchmark-led selections that need independent public scores
- Availability
- Limited preview
- Family
- GPT-5.6
- Released
- 2026-06-26
- Architecture
- Decoder Only
- Specialization
- general
- Openness
- Proprietary
- License
- ProprietaryCommercial use: conditional
Cheapest of 1 route · OpenAI API · cache read $0.100
About
OpenAI's fast, low-cost GPT-5.6 model. Luna is the affordable tier in the Sol, Terra, and Luna lineup, optimized for latency-sensitive applications such as summarization, drafting, autocomplete, and routine automation. It is available only to select trusted partners until broad API access launches.
GPT-5.6 Luna is a proprietary model in the GPT-5.6 family. The structured metadata tracks multimodal input, function calling, and tool use. This page tracks provider routes through OpenAI API, with the cheapest tracked route listed at $1 input and $6 output per 1M tokens. Headline tracked benchmarks include HealthBench Professional 55.7, HealthBench 55.8, and HealthBench Hard 32.0.
Top use-case fit: coding, agents, and build tasks
Agents
Included by capability and metadata signals in the decision map.
Vision
Included by capability and metadata signals in the decision map.
JSON / Tool use
Included by capability and metadata signals in the decision map.
Provider price ladder
Compare API pricing across 1 providers for input and output tokens, batch, and cached reads when available.
| Provider | Input / 1M | Output / 1M | Cache | Route |
|---|---|---|---|---|
| OpenAI API | $1.00 | $6.00 | read $0.100 | Serverless |
Available via routers & gateways(15)
AIRouter
RouterCommercial LLM router that analyzes incoming requests and routes to the optimal model for cost/quality/latency via a drop-in OpenAI-compatible API, with a privacy-preserving embedding mode that avoids sending prompt content.
Helicone
GatewayObservability-first AI gateway with routing, caching, rate limiting, and request tracing; Apache 2.0 open-source core with a managed hosted tier for logging and analytics.
Kong AI Gateway
GatewayMulti-LLM AI gateway built on Kong Gateway 3.x, adding semantic routing, load balancing, guardrails, and MCP traffic analytics as plugins over Kong's existing API management platform.
LiteLLM
GatewayOpen-source Python SDK and proxy server that unifies 100+ LLM APIs behind a single OpenAI-compatible interface, with load balancing, cost tracking, and configurable failover.
Martian
RouterAI-powered LLM router that analyzes each prompt in real-time to select the optimal model, targeting 20–97% cost reduction while maintaining quality; San Francisco startup reportedly nearing $1.3B valuation.
Neutrino AI
RouterCommercial LLM router that dynamically routes each query to the best-suited model with load balancing and fallback handling, charging 3% of underlying AI spend.
Capabilities
Benchmark peer barsfor Agents
No task-mapped benchmark peers are available for this model yet.
Benchmark scores(4)
| Benchmark | Score | Version | Source |
|---|---|---|---|
| HealthBench Professional | 55.7 | length-adjusted; raw 59.8; mean response 3389 chars | https://deploymentsafety.openai.com/gpt-5-6-preview |
| HealthBench | 55.8 | length-adjusted; raw 55.4; mean response 1930 chars | https://deploymentsafety.openai.com/gpt-5-6-preview |
| HealthBench Hard | 32.0 | length-adjusted; raw 31.4; mean response 1923 chars | https://deploymentsafety.openai.com/gpt-5-6-preview |
| HealthBench Consensus | 95.1 | length-adjusted; raw 95.1; mean response 1897 chars | https://deploymentsafety.openai.com/gpt-5-6-preview |
Migration checks
No linked migration route is available for this model yet.
Cheapest of 1 route · OpenAI API · cache read $0.100