WhichAI.todayClaude Fable 5.2
Anthropic
Pick this for the most difficult graduate-level reasoning, advanced proofs, and scientific research.
Skip it for everyday questions or routine math where standard models are faster and cheaper.
Humanity's Last Exam 74.3%.
Claude Fable 5.2 vs GPT-6 Astra
Updated Nov 12, 2026. Checked daily. Last checked Nov 13, 2026.
The short answer
Claude Fable 5.2 ranks ahead for reasoning, math & science. GPT-6 Astra ranks ahead for coding & software.
Claude Fable 5.2
1 of 2 jobs ahead
Paid plan
GPT-6 Astra
1 of 2 jobs ahead
Paid plan
Head to head, job by job
Each job ranks a #1, an alternative, and an open-weights pick from public leaderboards. Bars compare the two scores on that job's own signal.
Which one should you pick?
GPT-6 Astra
OpenAI
Pick this when you already work in ChatGPT or Codex.
Skip it if you want to run completely offline without sending source code to proprietary servers.
LMArena Code 1764; 90.2% on SWE-bench Pro V2 HARD
Price, access, and privacy
Claude Fable 5.2GPT-6 Astra
Cost
Pro is $20/month, or $17 if billed yearly. API is $8 per million input tokens and $40 per million output.
Plus is $20/month; API is $10 per million input tokens and $50 per million output tokens.
Free tier
Not on the free plan. Fable requires a paid plan or API access.
Not on the free plan. Plus includes access inside Work and Codex.
Where to get it
Apps
- Cursor, Premium ($30/month)
- Claude Code, Pro ($20/month)
- ChatGPT, Pro ($100/month)
- Perplexity, Max ($200/month)
- GitHub Copilot, Copilot Pro ($10/month)
- Codex, Plus ($20/month)
Trains on chats
Anthropic says Free, Pro, and Max chats are used for training only if you allow it, and you choose at signup. The toggle has been reported as on by default, so check it. Settings, then Privacy. Turn off Help improve Claude.
Yes on personal Free, Plus, and Pro. Improve the model for everyone is on by default. Settings, Data controls, turn off Improve the model for everyone.
Try both with the same prompt
Claude Fable 5.2
Solve this step by step, citing theorems used and highlighting any potential edge cases.
GPT-6 Astra
Implement this feature in the repo, then list the files you changed and why.
Want a sharper prompt? Build one for either model.
Ranking history
- Nov 12, 2026. Claude Fable 5.2 overtook Claude Opus 5.5. Humanity's Last Exam 74.3%.
Questions
Is Claude Fable 5.2 or GPT-6 Astra better for coding & software?
GPT-6 Astra ranks ahead for coding & software on LMArena Code. Claude Fable 5.2 is not in today's top three; GPT-6 Astra is the alternative pick (1764).
Is Claude Fable 5.2 or GPT-6 Astra better for reasoning, math & science?
Claude Fable 5.2 ranks ahead for reasoning, math & science on Humanity's Last Exam. Claude Fable 5.2 is the #1 pick (74.3); GPT-6 Astra is the alternative pick (57.2).
Which is cheaper, Claude Fable 5.2 or GPT-6 Astra?
Claude Fable 5.2: Pro is $20/month, or $17 if billed yearly. API is $8 per million input tokens and $40 per million output. GPT-6 Astra: Plus is $20/month; API is $10 per million input tokens and $50 per million output tokens.
Can I use Claude Fable 5.2 or GPT-6 Astra for free?
Claude Fable 5.2: Not on the free plan. Fable requires a paid plan or API access. GPT-6 Astra: Not on the free plan. Plus includes access inside Work and Codex.
Which is more private, Claude Fable 5.2 or GPT-6 Astra?
Claude Fable 5.2 (Anthropic): Anthropic says Free, Pro, and Max chats are used for training only if you allow it, and you choose at signup. The toggle has been reported as on by default, so check it. GPT-6 Astra (OpenAI): Yes on personal Free, Plus, and Pro. Improve the model for everyone is on by default.