AnthropicClaude Fable 5VSOpenAIGPT-5.6 Terra

Analysis by:the whichllmmodel Editorial Team|Updated: June 2026

Our Take

This matchup represents a clear tradeoff between peak intelligence and budget efficiency. Claude Fable 5 is noticeably superior (holding a 9.0% average lead in benchmarks), but it carries a significant 3.6x price premium. Choose Claude Fable 5 if you need top-tier reasoning or code debugging, but for high-volume pipelines, GPT-5.6 Terra is the smarter business decision.

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Model Specs

Claude Fable 5

Website

Benchmarks & Scores

Coding (swe-bench-pro)Winner (+16.9%)

80.3%

excellent at multi-file repositories, autonomous agents, and industrial codebases

Reasoning (gpqa-diamond)Winner (+1.2%)

94.1%

graduate-level science QA

Cost & Context

Cost (per 1M tokens)

$20.00Input: $10.00 | Output: $50.00

Context Window

1.05M tokens

Model Specs

GPT-5.6 Terra

Website

Benchmarks & Scores

Coding (swe-bench-pro)

63.4%

excellent at multi-file repositories, autonomous agents, and industrial codebases

Reasoning (gpqa-diamond)

92.9%

graduate-level science QA

Cost & Context

Cost (per 1M tokens)3.6x cheaper

$5.63Input: $2.50 | Output: $15.00

Context WindowLarger

1.05M tokens

Read our data collection methodology

Frequently Asked Questions about Claude Fable 5 vs GPT-5.6 Terra

GPT-5.6 Terra is cheaper than Claude Fable 5. GPT-5.6 Terra has a blended cost of $5.63/1M tokens, which is about 3.6x cheaper than Claude Fable 5 at $20.00/1M tokens.

Claude Fable 5 is better for coding tasks on this benchmark. It scores 80.3% on swe-bench-pro (excellent at multi-file repositories, autonomous agents, and industrial codebases) compared to GPT-5.6 Terra which scores 63.4%.

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