The AI arena is free today

Open Superagent

Claude Fable 5 vs GPT-5.6 Terra

Claude Fable 5 leads the LLM Stats Score 54.5 to 51.0. GPT-5.6 Terra is 4.4x cheaper per token.

Anthropic · OpenAI · Updated for 2026

Which is better?

Claude Fable 5 leads the overall LLM Stats Score 54.5 to 51.0, ranking #7 overall.

In the 9 individual benchmarks reported for both models, Claude Fable 5 wins 7; this is a narrower head-to-head signal than the composite indexes.

On price, GPT-5.6 Terra is roughly 4.4x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

GPT-5.6 Terra also accepts a larger context window (1,050,000 input tokens), making it the stronger choice for long documents and large codebases.

Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.

Choose Claude Fable 5

  • overall performance matters — it scores 54.5 and ranks #7 on LLM Stats
  • you value its reported benchmark strengths — it wins 7 of 9 exact shared results

Choose GPT-5.6 Terra

  • cost matters — it's about 4.4x cheaper per token
  • you process long inputs — it offers a 1,050,000 token context window
  • you want the most recent training data — it shipped Jul 2026

At a glance

The differences that matter most.

Core performance indexes
54.5
#7
51.0
#14
51.9
#9
49.3
#16
45.8
#3
42.4
#7
40.5
#5
38.1
#10
Cost, coverage & limits
Benchmark wins
7 of 9
2 of 9
Input price
$10.00 / M
$2.00 / M
Output price
$50.00 / M
$12.00 / M
Context window
1,000,000
1,050,000

Capability indexes

Additional strengths measured across groups of related public benchmarks

4 shared
Index
Claude Fable 5
GPT-5.6 Terra
41.3#8
32.4#58
36.1#9
29.9#29
26.8#26
30.2#17
31.8#23
30.7#28
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

19 reported for Claude Fable 5 · 45 for GPT-5.6 Terra

9 shared

Claude Fable 5 outperforms in 7 benchmarks (AutomationBench, ExploitBench, FrontierCode 1.1, GDP.pdf, HealthBench Professional, SWE-Bench Pro, Terminal-Bench 4.0), while GPT-5.6 Terra is better at 1 benchmark (Terminal-Bench 2.1).

Claude Fable 5 significantly outperforms across most benchmarks.

Thu Sep 10 2026 • llm-stats.com

Human preference

Blind head-to-head votes and playground preference scores

Pricing Analysis

Price comparison per million tokens

GPT-5.6 Terra costs less

For input processing, Claude Fable 5 ($10.00/1M tokens) is 5.0x more expensive than GPT-5.6 Terra ($2.00/1M tokens).

For output processing, Claude Fable 5 ($50.00/1M tokens) is 4.2x more expensive than GPT-5.6 Terra ($12.00/1M tokens).

In conclusion, Claude Fable 5 is more expensive than GPT-5.6 Terra.*

* Using a 3:1 ratio of input to output tokens

Lowest available price from all providers
Thu Sep 10 2026 • llm-stats.com
Anthropic
Claude Fable 5
Input tokens$10.00
Output tokens$50.00
Best providerAnthropic
OpenAI
GPT-5.6 Terra
Input tokens$2.00
Output tokens$12.00
Best providerOpenAI
Notice missing or incorrect data?Start an Issue

Context Window

Maximum input and output token capacity

GPT-5.6 Terra accepts 1,050,000 input tokens compared to Claude Fable 5's 1,000,000 tokens. Both models can generate responses up to 128,000 tokens.

Anthropic
Claude Fable 5
Input1,000,000 tokens
Output128,000 tokens
OpenAI
GPT-5.6 Terra
Input1,050,000 tokens
Output128,000 tokens
Thu Sep 10 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both Claude Fable 5 and GPT-5.6 Terra support multimodal inputs.

They are both capable of processing various types of data, offering versatility in application.

Claude Fable 5

Text
Images
Audio
Video

GPT-5.6 Terra

Text
Images
Audio
Video

License

Usage and distribution terms

Both models are licensed under proprietary licenses.

Both models have usage restrictions defined by their respective organizations.

Claude Fable 5

Proprietary

Closed source

GPT-5.6 Terra

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Fable 5 was released on 2026-06-09, while GPT-5.6 Terra was released on 2026-07-09.

GPT-5.6 Terra is 1 month newer than Claude Fable 5.

Claude Fable 5

Jun 9, 2026

3 months ago

GPT-5.6 Terra

Jul 9, 2026

2 months ago

1mo newer

Knowledge Cutoff

When training data ends

GPT-5.6 Terra has a documented knowledge cutoff of 2026-02-16, while Claude Fable 5's cutoff date is not specified.

We can confirm GPT-5.6 Terra's training data extends to 2026-02-16, but cannot make a direct comparison without Claude Fable 5's cutoff date.

Claude Fable 5

GPT-5.6 Terra

Feb 2026

Provider Availability

Claude Fable 5 is available from Anthropic, DeepInfra. GPT-5.6 Terra is available from OpenAI.

Claude Fable 5

anthropic logo
Anthropic
Input Price:Input: $10.00/1MOutput Price:Output: $50.00/1M
deepinfra logo
Deepinfra
Input Price:Input: $10.00/1MOutput Price:Output: $50.00/1M

GPT-5.6 Terra

openai logo
OpenAI
Input Price:Input: $2.00/1MOutput Price:Output: $12.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion

Judge for yourself.

Run your own prompts against Claude Fable 5 and GPT-5.6 Terra side-by-side, then vote on the output you prefer.

Claude Fable 5
✓ Preferred
GPT-5.6 Terra
Open in Playground

FAQ

Common questions about Claude Fable 5 vs GPT-5.6 Terra.

Which is better, Claude Fable 5 or GPT-5.6 Terra?

Claude Fable 5 leads the LLM Stats Score 54.5 to 51.0. Claude Fable 5 is made by Anthropic and GPT-5.6 Terra is made by OpenAI. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does Claude Fable 5 compare to GPT-5.6 Terra in benchmarks?

Claude Fable 5 scores SWE-Bench Verified: 95.0%, FrontierSWE: 90.0%, OSWorld-Verified: 85.0%, Terminal-Bench 2.1: 84.3%, SWE-Bench Pro: 80.0%. GPT-5.6 Terra scores Connectors: 100.0%, HealthBench Consensus: 95.1%, Search and Function-Calling: 94.6%, GPQA: 92.9%, Capture-the-Flag Challenges (Internal): 91.8%.

Is Claude Fable 5 cheaper than GPT-5.6 Terra?

GPT-5.6 Terra is 5.0x cheaper for input tokens. Claude Fable 5 costs $10.00/M input and $50.00/M output via anthropic. GPT-5.6 Terra costs $2.00/M input and $12.00/M output via openai.

What are the context window sizes for Claude Fable 5 and GPT-5.6 Terra?

Claude Fable 5 supports 1.0M tokens and GPT-5.6 Terra supports 1.1M tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Claude Fable 5 and GPT-5.6 Terra?

Key differences include LLM Stats Score (54.5 vs 51.0), context window (1.0M vs 1.1M), input pricing ($10.00 vs $2.00/M). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Fable 5 and GPT-5.6 Terra?

Claude Fable 5 is developed by Anthropic and GPT-5.6 Terra is developed by OpenAI.