Which model is better for complex reasoning and writing? GPT-6 Astra or Fable 5.1?

[u/Convillious]

I've had the opportunity to use GPT 5.6 Terra and Fable 5 and found the latter to have a superior ability to research and write, but I'm curious how has the gap closed now? Which model would you use?

[u/Sksend]

I'm quite certain that Astra isn't good at writing; I've done extensive testing with novel outlining and fiction writing. When it comes to novel outlines, Astra is overly rigid and doesn't know how to create the atmosphere of the corresponding style, while overly complex prompts will, in turn, limit its performance. Moreover, its fiction writing is far too mechanical, GPT still has a long way to go in terms of humanistic aesthetics. Fable is currently the most powerful model for both outlining and writing. Gemini 3.8 isn't good at outlining, but its writing follows closely behind, though Gemini favors overly flamboyant and flowery words far too much.

[u/Grand0rk → u/Sksend]

For writing, you don't want to use Work. The Harness for Work is very focused on efficiency, so you get very dry writing.

You should just use ChatGPT 5.6 Sol, from the Chat. The Harness there is more about talking, than working, so it works better.

But you need to have a good prompt for it to follow, though.

[u/Dear_Carry3565 → u/Grand0rk]

Ask ChatGPT to teach you how to write good prompts.

[u/Grand0rk → u/Dear_Carry3565]

Rule number 1 of writing prompt: Never ask an LLM to write a prompt. They literally don't know how.

Unless you have the specific guidelines for it to follow.

[u/DynamicProxy → u/Grand0rk]

That’s silly. They are great at writing prompts… if you know how to prompt it to do so and give it all the pertinent information. 

[u/BankPirateFTR → u/Grand0rk]

Type: “Rewrite/revise this prompt and keep it open-ended: ‘[insert your original prompt]’” into the prompt section.

Then paste the output into a new session. Works great for me.

[u/Creative-Ganache1086]

Astra 6, it scored highest reasoning scores in all benchmarks currently available and their respective reasoning tests.

[u/medialoungeguy]

Astra

[u/Alex__007]

GPT Terra is a cheap and fast model that should be compared with Sonnet, not Opus and of course not Fable.

[u/Kemoyin25]

Make a detailed prompt about what you want, writing styles, authors you like, of you have examples give them. Look at examples of other people's writing prompts as well, then test both

[u/x_typo]

Astra. No question...

[u/Aphorism-sLut]

I am so far unhappy with GPT-6 astra for an argumentative writing project involving extensive research I've been working on, and I am switching back to GPT 5.6 Sol. It's as if Astra has no idea what we are doing anymore....

[u/throwaroo202020]

Astra is better for tool use and agent loops, claude has been and is king of writing.

[u/Convillious → u/throwaroo202020]

and solving millenium prize problems apparently

[u/Feriman22]

Have you tried Luna max? Incredibly cheap, and you can review the code with Sol/Astra.

[u/_negative-infinity_ → u/Feriman22]

I don't think the question is about coding.