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OpenAI · Frontier

GPT 5.6 Sol Pro

Added Jul 9, 2026

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Use in the app

GPT-5.6 Sol 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
$10.00
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)
4.7K tokens
Longer than 98% of 473 models

Side by side

GPT 5.6 Sol 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 Sol ProOpenAIThis modelGPT 6 SolOpenAIRemove
ProviderOpenAIOpenAI
Discovery tierFrontierFrontier
AddedJul 9, 2026Sep 22, 2026
Limits
Context window1.05M1.05M
Max output128K128K
Average output4.7K tokens315 tokens
Pricing, USD per 1M tokens
Input$2.00$2.00
Output$10.00$10.00
Cache read$0.20$0.20
Cache write$2.50$2.50
Performance
Throughput574.6 tok/s—
Time to first token26.8 s—
Request success (24h)100.0%100.0%
Benchmark indexes
Intelligence Index47.0Best39.8
Coding Index77.4—
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 Sol Pro
  • GPT 6 Sol

Intelligence Index

  • GPT 5.6 Sol Pro47.0
  • GPT 6 Sol39.8

GPT 5.6 Sol Pro tested at max reasoning effort

GPT 5.6 Sol Pro: Better than 94% of 326 scored models

3.8Catalog models by score55.1

Indexes

  • Coding Index

    Composite of the coding evaluations

    • GPT 5.6 Sol Pro: 77.4
    • GPT 6 Sol: —

Agentic work

  • AutomationBench-AA

    Workflow automation, penalized for guardrail violations

    • GPT 5.6 Sol Pro: 60.1%Top
    • GPT 6 Sol: 58.0%

  • AutomationBench-AA tasks completed

    Workflows finished end to end without a guardrail violation

    • GPT 5.6 Sol Pro: 30.3%Top
    • GPT 6 Sol: 28.2%

  • AA-Briefcasev1.1

    Agentic knowledge work, rated head to head

    • GPT 5.6 Sol Pro: 1,479 EloTop
    • GPT 6 Sol: 1,148 Elo

  • GDPval-AAv2.1

    Economically valuable occupational tasks, rated head to head

    • GPT 5.6 Sol Pro: 1,609 EloTop
    • GPT 6 Sol: 1,346 Elo

Document reasoning

  • GDP.pdf

    Professional reasoning over PDF documents, all-pass rate

    • GPT 5.6 Sol Pro: 27.2%Top
    • GPT 6 Sol: 23.8%

  • AA-LCRv1.1

    Reasoning across long documents

    • GPT 5.6 Sol Pro: 84.0%Top
    • GPT 6 Sol: 82.3%

  • MLCR-AA

    Long-context reasoning over medical records

    • GPT 5.6 Sol Pro: 30.0%Top
    • GPT 6 Sol: 28.9%

Reasoning and knowledge

  • Humanity’s Last Exam

    Expert-level questions across academic fields

    • GPT 5.6 Sol Pro: 49.5%Top
    • GPT 6 Sol: 41.0%

  • GPQA Diamond

    Graduate-level science questions

    • GPT 5.6 Sol Pro: 94.1%
    • GPT 6 Sol: —

  • IFBench

    Following precise output instructions

    • GPT 5.6 Sol Pro: 72.7%
    • GPT 6 Sol: —

Coding

  • Terminal-Benchv4.0

    Practical software engineering in a terminal

    • GPT 5.6 Sol Pro: 39.9%Top
    • GPT 6 Sol: 18.7%

  • SciCode

    Scientific computing in Python

    • GPT 5.6 Sol Pro: 57.1%Top
    • GPT 6 Sol: 53.8%

Legacy evaluations

  • Terminal-Bench Hard

    Earlier terminal task suite

    • GPT 5.6 Sol Pro: 65.9%
    • GPT 6 Sol: —

  • τ²-Bench Telecom

    Tool use in a customer-support simulation

    • GPT 5.6 Sol Pro: 85.1%
    • GPT 6 Sol: —

  • AA-LCR (unversioned)

    Long-context reasoning, earlier grading

    • GPT 5.6 Sol Pro: 84.0%Top
    • GPT 6 Sol: 82.3%

Scores from Artificial Analysis, updated Oct 26, 2026. GPT 5.6 Sol 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.

Throughput
574.6 tok/s
Faster than 98% of 260 models
Time to first token
26.8 s
Quicker than 1% of 260 models
Prompt cache hits
66.6%
About $0.80 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-sol-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-sol-pro",
    messages=[{"role": "user", "content": "Explain this stack trace."}],
)
print(reply.choices[0].message.content)

OpenAI

Other OpenAI models, starting with the same family.