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OpenAI · Frontier

GPT 5.6 Terra Pro

Added Jul 9, 2026

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Use in the app

GPT-5.6 Terra with Pro reasoning mode. Pro mode performs more model work for difficult tasks; reasoning effort remains independently configurable and defaults to medium.

  • 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)
831 tokens
Longer than 65% of 465 models

Side by side

GPT 5.6 Terra Pro 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 Terra ProOpenAIThis modelGPT 6 SolOpenAIRemove
ProviderOpenAIOpenAI
Discovery tierFrontierFrontier
AddedJul 9, 2026Sep 22, 2026
Limits
Context window1.05M1.05M
Max output128K128K
Average output831 tokens315 tokens
Pricing, USD per 1M tokens
Input$2.00$2.00
Output$12.00$10.00Best
Cache read$0.20$0.20
Cache write$2.50$2.50
Performance
Request success (24h)—100.0%
Benchmark indexes
Intelligence Index42.1Best39.8
Coding Index76.7—
Capabilities
ReasoningYesYes
ToolsYesYes
VisionYesYes
Structured outputYesYes
PDF inputYesYes
Reasoning effortnone, low, medium, high, xhigh, maxnone, low, 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 Pro
  • GPT 6 Sol

Intelligence Index

  • GPT 5.6 Terra Pro42.1
  • GPT 6 Sol39.8

GPT 5.6 Terra Pro tested at max reasoning effort

GPT 5.6 Terra Pro: 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 Pro: 76.7
    • GPT 6 Sol: —

Agentic work

  • AutomationBench-AA

    Workflow automation, penalized for guardrail violations

    • GPT 5.6 Terra Pro: 59.6%Top
    • GPT 6 Sol: 58.0%

  • AutomationBench-AA tasks completed

    Workflows finished end to end without a guardrail violation

    • GPT 5.6 Terra Pro: 24.5%
    • GPT 6 Sol: 28.2%Top

  • AA-Briefcasev1.1

    Agentic knowledge work, rated head to head

    • GPT 5.6 Terra Pro: 1,332 EloTop
    • GPT 6 Sol: 1,148 Elo

  • GDPval-AAv2.1

    Economically valuable occupational tasks, rated head to head

    • GPT 5.6 Terra Pro: 1,452 EloTop
    • GPT 6 Sol: 1,346 Elo

Document reasoning

  • GDP.pdf

    Professional reasoning over PDF documents, all-pass rate

    • GPT 5.6 Terra Pro: 24.0%Top
    • GPT 6 Sol: 23.8%

  • AA-LCRv1.1

    Reasoning across long documents

    • GPT 5.6 Terra Pro: 83.0%Top
    • GPT 6 Sol: 82.3%

  • MLCR-AA

    Long-context reasoning over medical records

    • GPT 5.6 Terra Pro: 27.2%
    • GPT 6 Sol: 28.9%Top

Reasoning and knowledge

  • Humanity’s Last Exam

    Expert-level questions across academic fields

    • GPT 5.6 Terra Pro: 42.9%Top
    • GPT 6 Sol: 41.0%

  • GPQA Diamond

    Graduate-level science questions

    • GPT 5.6 Terra Pro: 92.5%
    • GPT 6 Sol: —

  • IFBench

    Following precise output instructions

    • GPT 5.6 Terra Pro: 71.2%
    • GPT 6 Sol: —

Coding

  • Terminal-Benchv4.0

    Practical software engineering in a terminal

    • GPT 5.6 Terra Pro: 35.4%Top
    • GPT 6 Sol: 18.7%

  • SciCode

    Scientific computing in Python

    • GPT 5.6 Terra Pro: 55.0%Top
    • GPT 6 Sol: 53.8%

Legacy evaluations

  • Terminal-Bench Hard

    Earlier terminal task suite

    • GPT 5.6 Terra Pro: 57.6%
    • GPT 6 Sol: —

  • τ²-Bench Telecom

    Tool use in a customer-support simulation

    • GPT 5.6 Terra Pro: 86.3%
    • GPT 6 Sol: —

  • AA-LCR (unversioned)

    Long-context reasoning, earlier grading

    • GPT 5.6 Terra Pro: 83.0%Top
    • GPT 6 Sol: 82.3%

Scores from Artificial Analysis, updated Oct 26, 2026. GPT 5.6 Terra Pro 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
10.3%
About $1.81 per 1M input tokens with caching

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.

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-pro",
    "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-pro",
    messages=[{"role": "user", "content": "Explain this stack trace."}],
)
print(reply.choices[0].message.content)

OpenAI

Other OpenAI models, starting with the same family.