GPT-5.6 Terra
Overview
GPT-5.6 Terra is OpenAI's balanced GPT-5.6 tier, made generally available on July 9, 2026. In the API, its model ID is gpt-5.6-terra, and OpenAI positions it for workloads that balance capability and cost.
Key Features
- Balanced GPT-5.6 Tier: Positioned between Sol and Luna for production workflows that need strong reasoning at lower cost than Sol.
- Expanded Reasoning Controls: Supports
none,low,medium,high,xhigh, andmaxreasoning effort; GPT-5.6 also supports Pro mode throughreasoning.mode: "pro". - Agentic Tooling: Supports Responses API workflows, functions, web search, file search, computer use, Programmatic Tool Calling, persisted reasoning, and multi-agent beta.
- Large Working Context: Supports a 1.05M-token context window and up to 128K output tokens, with a February 16, 2026 knowledge cutoff.
Best Use Cases
- Production Knowledge Work: Drafting, analysis, document processing, structured research, and multi-step business workflows.
- Software Engineering Assistance: Debugging, test planning, code review, repository navigation, and implementation support where cost control matters.
- Scaled Professional Automation: Tool-heavy workflows that need strong quality but do not require Sol for every request.
Capabilities and Limitations
| Capability | Description |
|---|---|
| Reasoning | Supports none, low, medium, high, xhigh, and max; API Pro mode is enabled with reasoning.mode: "pro" rather than a separate Pro model slug. |
| Coding | Official benchmark examples include SWE-Bench Pro 63.4%, DeepSWE v1.1 69.6%, and Terminal-Bench 2.1 87.4%. |
| Creative Writing | General text generation is supported. |
| Multimodal | Text and image input with text output; GPT-5.6 preserves original image dimensions for original or auto detail. |
| Response Speed | Public API latency depends on reasoning effort, tools, and processing tier; Terra is positioned as the balanced tier for intelligence and cost. |
| Context Window | 1.05M tokens. |
| Max Output | 128K tokens. |
| Tool Use | Functions, web search, file search, computer use, Programmatic Tool Calling, persisted reasoning, and multi-agent beta. |
| Multilingual | OpenAI API model documentation lists multilingual support across current models. |
Known Limitations
- Terra is positioned below Sol for capability, so the hardest quality-first workflows may need Sol, Pro mode, or higher reasoning effort.
- Higher reasoning efforts, Pro mode, multi-agent runs, and long-context use can increase latency and cost.
- Cyber and biology safeguards may refuse, block, or pause sensitive requests, including some legitimate dual-use work.
- Prompt cache writes are billed on GPT-5.6 models, so cache breakpoints should be monitored with
cache_write_tokensandcached_tokens.
Credits Usage
| Context | Input (Credits/Token) | Cache Write (Credits/Token) | Cache Read (Credits/Token) | Output (Credits/Token) | Web Search (Credits/Use) | Billing Notes |
|---|---|---|---|---|---|---|
| Short context | 2.50 | 3.125 | 0.25 | 15.00 | 10,000 | Standard GPT-5.6 Terra pricing |
| Long context (>272K input tokens) | 5.00 | 6.25 | 0.50 | 22.50 | 10,000 | Long-context pricing tier |
Pricing note
Prices shown in the documentation are B.AI standard reference prices for base billing purposes. B.AI may provide lower actual usage costs through top-up bonuses and account benefits. Specific prices, bonus Credits, and account benefits are subject to the platform display and final billing records.
- For GPT-5.6 models, cache writes are billed at 1.25x the uncached input rate; cache reads remain discounted at 0.1x input.