GPT-5.6 Terra
GPT-5.6 Terra is worth evaluating for rag, agents, and long context when its provider route and context window match the workload.
Use it for
- Teams evaluating rag, agents, and long context
- Workloads that can use a 1.05m context window
- Buyers comparing 2 tracked provider routes
Do not use it for
- Workloads where another current model has stronger sourced task evidence
- Family
- GPT-5.6
- Released
- 2026-07-09
- Context
- 1.05m
- Max output
- 128,000
- Architecture
- Decoder Only
- Specialization
- general
- Openness
- Proprietary
- License
- ProprietaryCommercial use: conditional
- Weights
- Not released
- Code
- Unknown
Cheapest of 2 routes · 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. Generally available July 9, 2026 across ChatGPT, Codex, and the OpenAI API (model ID gpt-5.6-terra). Supports text and image inputs, reasoning, tool use, prompt caching, and Batch API with a 1,050,000-token context window and 128K max output.
Top use-case fit: coding, agents, and build tasks
RAG
Included by capability and metadata signals in the decision map.
Agents
Included by capability and metadata signals in the decision map.
Long context
Included by capability and metadata signals in the decision map.
Provider price ladder
Compare all 2Compare API pricing across 2 providers for input and output tokens, batch, and cached reads when available.
| Provider | Input / 1M | Output / 1M | Batch in / out | Cache | Route |
|---|---|---|---|---|---|
| OpenAI API | $2.50 | $15.00 | $1.25 / $7.50 | read $0.250 | Serverless |
| OpenRouter | $2.50 | $15.00 | - | - | Serverless |
Available via routers & gateways(15)
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.
OpenRouter
HybridUnified hybrid gateway to 400+ models from 60+ providers via a single OpenAI-compatible API, with optional auto-routing that selects the best model per prompt.
Portkey
GatewayProduction AI gateway routing to 1,600+ LLMs with failover, load balancing, semantic caching, and guardrails; Apache 2.0 core is fully self-hostable with the complete feature set.
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.
Capabilities
Benchmark peer barsfor RAG
No task-mapped benchmark peers are available for this model yet.
Benchmark scores(15)
| Benchmark | Score | Version | Evaluation | Source |
|---|---|---|---|---|
| HealthBench Professional | 57.7 | length-adjusted; raw 62.4; mean response 3618 charsObserved 2026-06-26 | — | Source |
| HealthBench | 57.0 | length-adjusted; raw 58.7; mean response 2285 charsObserved 2026-06-26 | — | Source |
| HealthBench Hard | 32.7 | length-adjusted; raw 34.3; mean response 2199 charsObserved 2026-06-26 | — | Source |
| HealthBench Consensus | 95.1 | length-adjusted; raw 95.2; mean response 2247 charsObserved 2026-06-26 | — | Source |
| GeneBench-Pro | 28.5 | GPT Pro (Extended); max reasoning comparatorObserved 2026-06-30 | — | Source |
| CursorBench | 64.9 | CursorBench 3.2Observed 2026-07-18 | Configuration: GPT-5.6 Terra Max Harness: CursorBench 3.2 productized Cursor-agent workflow Evaluator: Cursor Confidence: confirmed Cost/task: $2.89 Tokens/task: 32,969 Steps/task: 47 Notes: Cursor vendor-reported result; not independently reproducible. Results are subject to variance, and small score differences may not be statistically meaningful. | Source |
| CursorBench | 59.2 | CursorBench 3.2Observed 2026-07-18 | Configuration: GPT-5.6 Terra Extra High Harness: CursorBench 3.2 productized Cursor-agent workflow Evaluator: Cursor Confidence: confirmed Cost/task: $1.44 Tokens/task: 16,089 Steps/task: 29 Notes: Cursor vendor-reported result; not independently reproducible. Results are subject to variance, and small score differences may not be statistically meaningful. | Source |
| CursorBench | 54.2 | CursorBench 3.2Observed 2026-07-18 | Configuration: GPT-5.6 Terra High Harness: CursorBench 3.2 productized Cursor-agent workflow Evaluator: Cursor Confidence: confirmed Cost/task: $0.89 Tokens/task: 9,468 Steps/task: 23 Notes: Cursor vendor-reported result; not independently reproducible. Results are subject to variance, and small score differences may not be statistically meaningful. | Source |
| CursorBench | 50.3 | CursorBench 3.2Observed 2026-07-18 | Configuration: GPT-5.6 Terra Medium Harness: CursorBench 3.2 productized Cursor-agent workflow Evaluator: Cursor Confidence: confirmed Cost/task: $0.61 Tokens/task: 6,222 Steps/task: 20 Notes: Cursor vendor-reported result; not independently reproducible. Results are subject to variance, and small score differences may not be statistically meaningful. | Source |
| CursorBench | 46.9 | CursorBench 3.2Observed 2026-07-18 | Configuration: GPT-5.6 Terra Low Harness: CursorBench 3.2 productized Cursor-agent workflow Evaluator: Cursor Confidence: confirmed Cost/task: $0.53 Tokens/task: 5,312 Steps/task: 19 Notes: Cursor vendor-reported result; not independently reproducible. Results are subject to variance, and small score differences may not be statistically meaningful. | Source |
| CursorBench | 41.3 | CursorBench 4.0Observed 2026-09-10 | Configuration: GPT-5.6 Terra Max Harness: CursorBench 4.0 productized Cursor-agent workflow Evaluator: Cursor Confidence: confirmed Cost/task: $5.14 Tokens/task: 60,814 Steps/task: 107 Notes: Cursor vendor-reported configuration result; not independently reproducible. Results are subject to variance, and small score differences may not be statistically meaningful. | Source |
| CursorBench | 33.6 | CursorBench 4.0Observed 2026-09-10 | Configuration: GPT-5.6 Terra Extra High Harness: CursorBench 4.0 productized Cursor-agent workflow Evaluator: Cursor Confidence: confirmed Cost/task: $1.81 Tokens/task: 23,436 Steps/task: 43 Notes: Cursor vendor-reported configuration result; not independently reproducible. Results are subject to variance, and small score differences may not be statistically meaningful. | Source |
| CursorBench | 30.7 | CursorBench 4.0Observed 2026-09-10 | Configuration: GPT-5.6 Terra High Harness: CursorBench 4.0 productized Cursor-agent workflow Evaluator: Cursor Confidence: confirmed Cost/task: $1.11 Tokens/task: 13,162 Steps/task: 33 Notes: Cursor vendor-reported configuration result; not independently reproducible. Results are subject to variance, and small score differences may not be statistically meaningful. | Source |
| CursorBench | 27.6 | CursorBench 4.0Observed 2026-09-10 | Configuration: GPT-5.6 Terra Medium Harness: CursorBench 4.0 productized Cursor-agent workflow Evaluator: Cursor Confidence: confirmed Cost/task: $0.64 Tokens/task: 7,307 Steps/task: 25 Notes: Cursor vendor-reported configuration result; not independently reproducible. Results are subject to variance, and small score differences may not be statistically meaningful. | Source |
| CursorBench | 25.2 | CursorBench 4.0Observed 2026-09-10 | Configuration: GPT-5.6 Terra Low Harness: CursorBench 4.0 productized Cursor-agent workflow Evaluator: Cursor Confidence: confirmed Cost/task: $0.52 Tokens/task: 5,914 Steps/task: 23 Notes: Cursor vendor-reported configuration result; not independently reproducible. Results are subject to variance, and small score differences may not be statistically meaningful. | Source |
Migration checks
No linked migration route is available for this model yet.
Rankings & picks(2)
Cheapest of 2 routes · OpenAI API · cache read $0.250