GPT-5.6 Terra
GPT-5.6 Terra 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 Terra'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 $0.250
About
OpenAI's balanced mid-tier GPT-5.6 model. Terra delivers performance competitive with GPT-5.5 at about 2x lower cost, suited for high-volume production workloads such as customer support, document analysis, and internal tooling. It introduces the GPT-5.6 family preview tiering and is available only to select trusted partners until broad API access launches.
GPT-5.6 Terra is a proprietary model in the GPT-5.6 family. The structured metadata tracks multimodal input, reasoning, function calling, and tool use. This page tracks provider routes through OpenAI API, with the cheapest tracked route listed at $2.5 input and $15 output per 1M tokens. Headline tracked benchmarks include HealthBench Professional 57.7, HealthBench 57.0, and HealthBench Hard 32.7.
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 | $2.50 | $15.00 | read $0.250 | 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 | 57.7 | length-adjusted; raw 62.4; mean response 3618 chars | https://deploymentsafety.openai.com/gpt-5-6-preview |
| HealthBench | 57.0 | length-adjusted; raw 58.7; mean response 2285 chars | https://deploymentsafety.openai.com/gpt-5-6-preview |
| HealthBench Hard | 32.7 | length-adjusted; raw 34.3; mean response 2199 chars | https://deploymentsafety.openai.com/gpt-5-6-preview |
| HealthBench Consensus | 95.1 | length-adjusted; raw 95.2; mean response 2247 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 $0.250