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OpenAI · Frontier

GPT 5.6 Terra

Added Jul 9, 2026

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Use in the app

GPT-5.6 Terra is the balanced model in OpenAI's GPT-5.6 series, positioned between flagship Sol and cost-efficient Luna. It is suited for everyday coding, reasoning, agentic work, and general professional tasks.

  • Reasoning
  • Tools
  • Vision
  • Structured output
  • PDF input
Input
Text, Images
Output
Text
Reasoning effort
none · low · medium · high · xhigh · max
Discovery tier
Frontier

Pricing

USD per 1M tokens
Input
$2.00
Output
$12.00
Cache read
$0.20
Cache write
$2.50

Reference prices as published by the model provider. API example

Specifications

Context window
1.1M
Max output
128K
Average output (7 days)
556 tokens
Longer than 52% of 465 models

Side by side

GPT 5.6 Terra compared

Specifications, prices, speed and benchmark scores next to each other. Benchmarks below show every compared model too.

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GPT 5.6 TerraOpenAIThis modelClaude Opus 4.8AnthropicRemove
ProviderOpenAIAnthropic
Discovery tierFrontierFrontier
AddedJul 9, 2026May 28, 2026
Limits
Context window1.05MBest1M
Max output128K128K
Average output556 tokens360 tokens
Pricing, USD per 1M tokens
Input$2.00Best$5.00
Output$12.00Best$25.00
Cache read$0.20Best$0.50
Cache write$2.50—
Performance
Throughput—72.8 tok/s
Time to first token—1.0 s
Request success (24h)100.0%100.0%
Benchmark indexes
Intelligence Index42.1Best41.8
Coding Index76.7Best74.3
Capabilities
ReasoningYesYes
ToolsYesYes
VisionYesYes
Structured outputYesYes
PDF inputYesYes
Reasoning effortnone, low, medium, high, xhigh, maxlow, medium, high, xhigh, max

Public evaluations

Benchmarks

Independent evaluation results, with how each score ranks among the models in the Noumen catalog.

  • GPT 5.6 Terra
  • Claude Opus 4.8

Intelligence Index

  • GPT 5.6 Terra42.1
  • Claude Opus 4.841.8

GPT 5.6 Terra tested at max reasoning effort

GPT 5.6 Terra: Better than 87% of 326 scored models

3.8Catalog models by score55.1

Indexes

  • Coding Index

    Composite of the coding evaluations

    • GPT 5.6 Terra: 76.7Top
    • Claude Opus 4.8: 74.3

Agentic work

  • AutomationBench-AA

    Workflow automation, penalized for guardrail violations

    • GPT 5.6 Terra: 59.6%Top
    • Claude Opus 4.8: 45.6%

  • AutomationBench-AA tasks completed

    Workflows finished end to end without a guardrail violation

    • GPT 5.6 Terra: 24.5%Top
    • Claude Opus 4.8: 17.4%

  • AA-Briefcasev1.1

    Agentic knowledge work, rated head to head

    • GPT 5.6 Terra: 1,332 EloTop
    • Claude Opus 4.8: 1,319 Elo

  • GDPval-AAv2.1

    Economically valuable occupational tasks, rated head to head

    • GPT 5.6 Terra: 1,452 Elo
    • Claude Opus 4.8: 1,454 EloTop

Document reasoning

  • GDP.pdf

    Professional reasoning over PDF documents, all-pass rate

    • GPT 5.6 Terra: 24.0%Top
    • Claude Opus 4.8: 22.8%

  • AA-LCRv1.1

    Reasoning across long documents

    • GPT 5.6 Terra: 83.0%Top
    • Claude Opus 4.8: 77.7%

  • MLCR-AA

    Long-context reasoning over medical records

    • GPT 5.6 Terra: 27.2%Top
    • Claude Opus 4.8: 19.4%

Reasoning and knowledge

  • Humanity’s Last Exam

    Expert-level questions across academic fields

    • GPT 5.6 Terra: 42.9%
    • Claude Opus 4.8: 48.7%Top

  • GPQA Diamond

    Graduate-level science questions

    • GPT 5.6 Terra: 92.5%Top
    • Claude Opus 4.8: 92.0%

  • IFBench

    Following precise output instructions

    • GPT 5.6 Terra: 71.2%Top
    • Claude Opus 4.8: 62.2%

Coding

  • Terminal-Benchv4.0

    Practical software engineering in a terminal

    • GPT 5.6 Terra: 35.4%Top
    • Claude Opus 4.8: 21.7%

  • SciCode

    Scientific computing in Python

    • GPT 5.6 Terra: 55.0%Top
    • Claude Opus 4.8: 54.4%

Legacy evaluations

  • Terminal-Bench Hard

    Earlier terminal task suite

    • GPT 5.6 Terra: 57.6%
    • Claude Opus 4.8: 58.3%Top

  • τ²-Bench Telecom

    Tool use in a customer-support simulation

    • GPT 5.6 Terra: 86.3%
    • Claude Opus 4.8: 94.4%Top

  • AA-LCR (unversioned)

    Long-context reasoning, earlier grading

    • GPT 5.6 Terra: 83.0%Top
    • Claude Opus 4.8: 77.7%

Scores from Artificial Analysis, updated Oct 26, 2026. GPT 5.6 Terra was tested at max reasoning effort; compare scores measured at the same effort.Artificial Analysis

Live routing data

Performance and reliability

Recent averages across requests routed for this model. Your own speed depends on prompt length, reasoning effort and load.

Prompt cache hits
81.5%
About $0.53 per 1M input tokens with caching
Request success (24h)
100.0%
Reliable

Cache hits are the share of input tokens recently served from a prompt cache across all requests. They are not a forecast of your own hit rate.

Hourly request success · last 72 hoursLowest hour 100.0%
  • Healthy (98% or more)
  • Degraded (90–98%)
  • Down (under 90%)
  • No requests

Developers

Use it through the API

Noumen’s API is OpenAI-compatible: any Chat Completions client works with a base URL and a key.

Read the quickstart
curl https://www.noumen.xyz/api/v1/chat/completions \
  -H "Authorization: Bearer $NOUMEN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai/gpt-5.6-terra",
    "reasoning_effort": "medium",
    "messages": [{ "role": "user", "content": "Explain this stack trace." }]
  }'
import os
from openai import OpenAI

client = OpenAI(base_url="https://www.noumen.xyz/api/v1", api_key=os.environ["NOUMEN_API_KEY"])
reply = client.chat.completions.create(
    model="openai/gpt-5.6-terra",
    messages=[{"role": "user", "content": "Explain this stack trace."}],
)
print(reply.choices[0].message.content)

OpenAI

Other OpenAI models, starting with the same family.