> ## Documentation Index
> Fetch the complete documentation index at: https://docs.apiyi.com/llms.txt
> Use this file to discover all available pages before exploring further.
# GPT-5.6 Series Launch: Sol, Terra and Luna
> OpenAI's next-gen GPT-5.6 trio is live on APIYI: flagship Sol at $5/$30, balanced Terra at $2.5/$15, lightweight Luna at $1/$6 — official price parity, up to 20% recharge bonus (~17% off) on the default relay group, and a 0.7x discount on the CodexReverse group.
## Key Takeaways
* **Three tiers at once**: OpenAI released the GPT-5.6 series on July 9, 2026 — flagship `gpt-5.6-sol`, balanced `gpt-5.6-terra`, and lightweight `gpt-5.6-luna` — and all three are live on APIYI
* **New naming system**: the number marks the model generation while Sol / Terra / Luna are durable capability tiers that advance on their own cadence, replacing the old Pro / Mini / Nano suffixes
* **Clear gains over GPT-5.5**: Sol hits **88.8%** on Terminal-Bench 2.1 (GPT-5.5: 85.6%), **90.4%** on BrowseComp, and **52.7%** on Agents' Last Exam; Terra matches GPT-5.5-level performance at **half the price**
* **Programmatic Tool Calling**: the Responses API gains programmatic tool calling — model-written JavaScript runs in an isolated, network-less V8 runtime, with customers reporting 38-63.5% token reductions
* **Dual-channel supply**: the default official-relay group is at official price parity (recharge bonus up to 20%, roughly **17% off effective**); the CodexReverse group carries a default **0.7x discount**
## Background
On July 9, 2026, OpenAI moved the GPT-5.6 series from limited preview to general availability across ChatGPT, Codex, and the OpenAI API. The headline change is the naming system: instead of Pro / Mini / Nano suffixes, the family introduces three celestial capability tiers — Sol (flagship), Terra (balanced), Luna (lightweight) — where the number identifies the generation and each tier can evolve on its own schedule.
The positioning is equally crisp: Sol pushes the frontier on agentic tasks, Terra delivers GPT-5.5-class performance at half the cost, and Luna drops the entry price to \$1/\$6 per million tokens. APIYI shipped all three models the day after release, on both the default official-relay group and the CodexReverse group.
## Deep Dive
### Benchmarks (data retrieved 2026/7/10)
| Benchmark | Sol | Terra | Luna | GPT-5.5 | Claude Fable 5 |
| -------------------------- | --------- | ----- | ----- | ------- | -------------- |
| AA Coding Agent Index v1.1 | **80** | 77.4 | 74.6 | 76.4 | 77.2 |
| Terminal-Bench 2.1 | **88.8%** | 87.4% | 84.7% | 85.6% | 83.1% |
| DeepSWE v1.1 | **72.7%** | 69.6% | 67.2% | 67% | 69.7% |
| SWE-Bench Pro | 64.6% | 63.4% | 62.7% | 59.4% | **80%** |
| Agents' Last Exam | **52.7%** | 50.4% | 50.3% | 46.9% | 40.5% |
| BrowseComp | **90.4%** | 87.5% | 83.3% | 84.4% | — |
| OSWorld 2.0 | **62.6%** | 50.2% | 45.6% | 47.5% | — |
Sources: the official OpenAI announcement at `openai.com/index/gpt-5-6` and `marktechpost.com` (July 9, 2026). The multi-agent Sol Ultra configuration (4 agents) reaches 91.9% on Terminal-Bench 2.1. Note: Claude Fable 5 (80%) still leads Sol (64.6%) by a wide margin on SWE-Bench Pro.
### Core Features
Sol for the ceiling, Terra for the daily workhorse, Luna for cost control — same generation and lineage, switchable by just changing the `model` name in the OpenAI-compatible format
New in the Responses API: model-written JavaScript executes in an isolated, network-less V8 runtime, with named customers reporting 38-63.5% token reductions
Cache writes bill at 1.25x the uncached input rate; cache reads keep the 90% discount with a 30-minute minimum cache lifetime
Leads its predecessor across BrowseComp, OSWorld 2.0 and Agents' Last Exam, with major gains in browser and desktop automation
Luna scores only 41.3% on the 256K-1M long-context evaluation — for very long documents, prefer Terra / Sol or chunk the input.
## Practical Use
### Which Tier to Pick
* **`gpt-5.6-sol`**: ceiling-bound agentic work — complex coding agents, desktop / browser automation, deep research
* **`gpt-5.6-terra`**: the daily driver — GPT-5.5-class performance at half the price, the natural migration target for most production workloads
* **`gpt-5.6-luna`**: high-volume traffic — classification, extraction, light chat, tool-calling glue
### Code Example
```python theme={null}
import openai
client = openai.OpenAI(
api_key="your-apiyi-key",
base_url="https://api.apiyi.com/v1"
)
response = client.chat.completions.create(
model="gpt-5.6-terra", # or gpt-5.6-sol / gpt-5.6-luna
messages=[
{"role": "user", "content": "Summarize the differences between the three GPT-5.6 tiers"}
]
)
print(response.choices[0].message.content)
```
Existing GPT-5.5 code migrates by swapping the `model` field.
## Pricing & Availability
### Pricing (per 1M tokens, matching official rates)
| Model | Input | Output | Tier |
| --------------- | ------ | ------- | ----------- |
| `gpt-5.6-sol` | \$5.00 | \$30.00 | Flagship |
| `gpt-5.6-terra` | \$2.50 | \$15.00 | Balanced |
| `gpt-5.6-luna` | \$1.00 | \$6.00 | Lightweight |
### Two Supply Groups
| Group | Pricing | Notes |
| --------------------------------------- | ------------------------- | --------------------------------------------------------------------------------------- |
| Default official relay (default / svip) | Official parity | Official API resources; recharge bonus up to 20%, effectively about **17% off** (1/1.2) |
| CodexReverse | Default **0.7x discount** | Codex reverse-engineered economy channel; availability tracks official Codex |
Pick by need: the default official-relay group for production-grade stability, the CodexReverse group for cost-sensitive batch workloads. See the [recharge promotions guide](/en/faq/recharge-promotions).
## Summary & Recommendations
The real story of GPT-5.6 isn't any single benchmark — it's the tiered product structure. Terra delivers GPT-5.5-class performance at half the price and is the tier most worth migrating to first; Sol tops nearly every agentic benchmark (except SWE-Bench Pro, where Claude Fable 5 keeps a \~15-point lead); Luna gives high-concurrency workloads a new \$1-input option. Run your existing workload through Terra first, and step up to Sol for agent-heavy scenarios.
Sources: the official OpenAI announcement at `openai.com/index/gpt-5-6`, the OpenAI Help Center, MarkTechPost, and VentureBeat; data retrieved July 10, 2026. All three models are live on APIYI — grab a key and start calling.