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ModelCap

GPT-5.6 Terra

Current board #22Arena #45API only

OpenAI·openai/gpt-5.6-terra

GPT-5.6 Terra is ModelCap current-board rank #22 with Index 77.5 (Measured), from the ModelCap Index as of 22 Sept 2026, 02:49 UTC.

GPT-5.6 Terra listed OpenRouter input price is $2.00 per 1M tokens and listed output price is $12.00 per 1M tokens, from OpenRouter listed prices as of 22 Sept 2026, 02:49 UTC.

GPT-5.6 Terra has a published context limit of 1M tokens in the ModelCap catalogue as of 22 Sept 2026, 02:49 UTC.

GPT-5.6 Terra has 7 published OpenRouter serving endpoints, from OpenRouter as of 22 Sept 2026, 02:49 UTC.

GPT-5.6 Terra weight access is api only, from ModelCap classification of published repository metadata as of 22 Sept 2026, 02:49 UTC.

Snapshot facts · download the public dataset · methodology

ModelCap Index · Current board
77.5#22
Measured · 89% support · score interval 71.8–83.2
Evidence as of 21 Sept 2026, 17:21 UTC
Market Gravity
54.9
Secondary market signal
Input
$2.00
per 1M tokens
Output
$12.00
per 1M tokens
Context
1M
tokens
Providers
7
endpoints
Gateway spend
latest · Vercel share

Providers

Uptime measured over the last 30 minutes
ProviderInputOutputContextQuantUptime
OpenAIflexCheapest$1.00$6.001M100.0%
Azure$2.00$12.001M100.0%
OpenAI$2.00$12.001M100.0%
Azureus$2.20$13.201M
Amazon Bedrockus-east-1$2.20$13.201M
Azureeu$2.20$13.201M
OpenAIfast$4.00$24.001M100.0%

Reasoning efforts

Best supported result can inform ModelCap

Published Max, X-High, High and other configurations for this model. These are sourced scores, not head-to-head essays.

EffortAgent scoreSource rankSampleSource
X-High
GPT 5.6 Terra (xHigh)
1.44%
CI 0.32.6%
#231.2M obs
20K sessions
LMArena Agent
Match 100%

Related community configurations

Human preference rating
ConfigurationRatingSource rankVotesSource
X-High
gpt-5.6-terra-xhigh
1466
CI 1461–1471
#4528KLMArena
Match 100%

ModelCap Index · Current board

Methodology
77.5
Measured · 6 public benchmark observations across 6 boards
Current board
#22
Public rank basis
Measured (measured)
Index support
88.7% · strong
Index interval
71.8–83.2
Rank posterior
Not available
Top 5 / Top 10 probability
Not available / Not available
Posterior as of
Snapshot timestamp unavailable
Evidence as of
21 Sept 2026, 17:21 UTC
Identity binding
Exact catalogue product · openai/openai/gpt-5.6-terra · aggregates disclosed benchmark configurations · endpoint configuration not claimed
Index observations used
6
Qualified Index evidence point
77.5
Bayesian Evidence Score · measured evidence input only

BES normalizes admitted public benchmark evidence for measured Index rows. Its legacy score and observables prior do not define the public language rank.

Observed capability
77.5
Evidence status
confirmed · 97% mass
General preference
79.3
Coding
79.4
Agents & tools
47.3
Reasoning
60.3
Evidence breadth
100%
Evidence coverage
89%
Market and catalogue signals · secondary, never the language Index rank
Usage (OpenRouter popularity)
40.5
Liquidity (providers × uptime)
85.3
Open reach (HF downloads)
Surface (context / tools / modalities)
100.0
Freshness
75.2
  • · OpenRouter popularity #31
  • · 3 live providers
  • · Catalogue: context 1050000, reasoning, tools, modalities File/Image/Text
  • · First seen 2026-07-09

These adoption and deployment observations remain context only. They do not change this model's ModelCap Index score or rank.

BES evidence selected · measured input only

The bounded 0–100 capability score blends each source’s competitive placement with its published achievement, then combines capability families. Evidence breadth adds a modest uncertainty adjustment; price and popularity are not part of benchmark-led rank.

Deployment readiness

Metadata index
54.0
partial · 56% metadata coverage
Not capability
Artifact reproducibility
0.0
Access & legal clarity
30.3
Deployability
100.0
Evaluation provenance
89.7

Missing: artifactReproducibility.revision-sha, artifactReproducibility.architecture-and-model-type, artifactReproducibility.parameter-count, artifactReproducibility.serialized-weight-format, artifactReproducibility.base-lineage, accessLegalClarity.declared-license, accessLegalClarity.resolvable-license-terms, evaluationProvenance.evaluation-dataset-revisions.

A metadata completeness and deployability index—not a safety certification, quality grade, or production-readiness claim.

Market activity

Venue coverage
Market Gravity
54.9
OpenRouter weekly popularity
#31 of 322

Market Gravity uses OpenRouter’s full-catalogue popularity order. Sparse Vercel top-ten observations appear only when published and do not affect the score.

Arena preference

Status
Ranked
Source
LMArena
Official rank
#45 of 402
Rating
1466.0
95% confidence interval
1461–1471
Votes
28K
Source published at
13 Sept 2026, 00:00 UTC
Category
overall
Identity match confidence
100%

Market Gravity breakdown

Usage55%
40.5

OpenRouter weekly popularity across the full model catalogue.

Liquidity25%
85.3

Independent providers versus the model's open or closed cohort, weighted by uptime.

Open reach15%
50.0

Hugging Face 30-day downloads for open models; neutral for closed models.

Freshness5%
75.2

Time since first public availability, on a six-month half-life.

Specification

Context window
1M tokens
Max output
128K tokens
Inputs
File, Image, Text
Outputs
Text
Tokenizer
GPT
Cached input tokens
$0.20 / 1M
First seen on OpenRouter
9 Jul 2026
Knowledge cutoff
2026-02-16

Capabilities

  • Supported: Reasoning
  • Supported: Tool use
  • Supported: Structured output
  • Supported: Response format
  • Supported: Moderated

Compare GPT-5.6 Terra with

Pick any model

Benchmark leaderboards featuring GPT-5.6 Terra

All leaderboards
Public benchmark boards on which GPT-5.6 Terra has a published result
LeaderboardScoreSource rankConfigurationPublished
Arena coding leaderboardArena (LMArena)15181510–1525#35 of 397X-High13 Sept 2026
LMArena Agent leaderboardLMArena1.4%0.3%–2.6%#23 of 46X-High15 Sept 2026
ARC-AGI-2 leaderboardARC Prize Foundation83.9%#23 of 214Max21 Sept 2026
ARC-AGI-3 leaderboardARC Prize Foundation0.8%#20 of 39Max21 Sept 2026
Artificial Analysis Intelligence IndexArtificial Analysis42.1#31 of 151intelligence-index:v4.3:max19 Sept 2026
τ²-Bench Telecom (Artificial Analysis run)Artificial Analysis86.3%#92 of 436tau2:telecom:dual-control:pass-at-1:3-repeats:source-model="GPT-5.6 Terra (max)":reasoning=true5 Sept 2026
Humanity's Last Exam (Artificial Analysis run)Artificial Analysis42.9%#38 of 615hle:may-2025:text-only-2158:no-tools:pass-at-1:source-model="GPT-5.6 Terra (max)":reasoning=true5 Sept 2026
Terminal-Bench 4.0 leaderboardTerminal-Bench (Laude Institute)21.5%18.3%–24.8%#21 of 27Codex · Max26 Jun 2026

Alternatives to GPT-5.6 Terra, by the numbers

Ranked neighbours

Models within 3 places of #22 on the ModelCap Index.

Cheaper at a similar or higher Index

Index score within 3 points of, or above, this model's, with a lower listed blended price (3:1 input:output).

Other ranked OpenAI models

The same publisher's other current models with a public Index position.

GPT-5.6 Terra: common questions

How does GPT-5.6 Terra rank among AI models?

GPT-5.6 Terra holds ModelCap Index position #22 of 248 ranked language models as of 22 September 2026, with an Index score of 77.5 (interval 71.8–83.2); evidence: measured. The Index combines public benchmark boards with published uncertainty; the methodology page explains the weighting.

How much does GPT-5.6 Terra cost per 1M tokens?

GPT-5.6 Terra is listed at $2.00 per 1M input tokens and $12.00 per 1M output tokens as of 22 September 2026; the lowest output price among 3 providers is $6.00 on OpenAI. Prices come from the OpenRouter catalogue and re-observe on every refresh. For 1,000 requests using 2,000 input and 500 output tokens each, the listed rates imply $10.00 total (2M input + 0.5M output). This excludes caching, batch discounts, prompt-length tiers, tool charges and retries; verify the chosen endpoint's rate and limits before budgeting.

What is the context window of GPT-5.6 Terra?

GPT-5.6 Terra has a published context window of 1M tokens (1,050,000) and a maximum output of 128K tokens. Individual providers can serve less than the published maximum; the providers table lists each endpoint's own limit.

Is GPT-5.6 Terra open-weight?

API only. No downloadable model weights are linked in the current source data; access is through a hosted API or product.

Which API providers serve GPT-5.6 Terra?

3 providers serve GPT-5.6 Terra through OpenRouter as of 22 September 2026: OpenAI, Azure and Amazon Bedrock. Each provider's price, context limit, quantization and measured uptime are in the providers table above.

Which benchmarks has GPT-5.6 Terra been evaluated on?

GPT-5.6 Terra has published results on 8 public boards tracked by ModelCap as of 22 September 2026: Arena coding 1518 (#35 of 397), LMArena Agent 1.4% (#23 of 46), ARC-AGI-2 83.9% (#23 of 214), ARC-AGI-3 0.8% (#20 of 39) and AA Intelligence Index 42.1 (#31 of 151) and more. Each board page ranks every tracked model on that benchmark; the ModelCap Index combines them with published uncertainty.

How does GPT-5.6 Terra compare with Nex-N2.5-Pro?

GPT-5.6 Terra ranks #22 (Index 77.5) and Nex-N2.5-Pro ranks #21 (Index 77.6) on the ModelCap Index as of 22 September 2026. The head-to-head page lines up their benchmarks, listed prices, context windows and provider counts side by side.

When was GPT-5.6 Terra released?

GPT-5.6 Terra first appeared in the catalogue on 9 Jul 2026, with a published knowledge cutoff of 2026-02-16. It is the current version in its family. Rank and price movements since then are recorded on the site's changes feed.