GPT-6 Astra and Claude Fable 5.1 start at the same headline API prices, but they did not behave the same in our matched compatibility-API tests. Astra returned more usable visible output across reasoning, writing, coding, long-context retrieval, and strategy. Fable tied the long-context accuracy test and wrote credible launch copy, yet several runs were truncated or blank in this particular route.

บทสรุปสั้นๆ
GPT-6 Astra · 43/50
Long-context retrieval · 10/10 each
Compatibility routing may explain Fable’s blank outputs.
Choose GPT-6 Astra when you need a dependable first-pass answer across mixed analytical and technical work. Choose Claude Fable 5.1 when your own endpoint has been validated for visible-output handling and you value its long-context interpretation or measured prose. This is not a universal model ranking: it is one controlled run through Broly Anywhere on September 8, 2026.
GPT-6 Astra vs Claude Fable 5.1 at a glance
| สนาม | GPT-6 Astra | Claude Fable 5.1 |
|---|---|---|
| API ID | gpt-6-astra | claude-fable-5-1 |
| บริบท | 1.05 ล้านโทเค็น | 1 ล้านโทเค็น |
| กำลังออกสูงสุด | โทเค็น 128K | โทเค็น 128K |
| ข้อมูลนำเข้าพื้นฐาน | $10 / 1M | $10 / 1M |
| Cached input / hit | $1 / 1M | $0.25 / 1M |
| ผลลัพธ์ | $50 / 1M | $50 / 1M |
| ชุด | 50% of standard | $5 input / $25 output per 1M |
| เหตุผล | ความพยายามในการให้เหตุผลที่ปรับแต่งได้ | Adaptive thinking, always on; high default |
| Observed test score | 43/50 | 19/50 |

For deeper model context, see our GPT-6 Astra review, Claude Fable 5.1 guide, และ Claude model comparison.
Pricing, caching, context, and limits
Both models list $10 per million base input tokens and $50 per million output tokens. The operational difference is caching. GPT-6 Astra lists $1 per million cached input tokens and a $12.50 cache-write rate. Fable 5.1 lists $0.25 cache hits, $12.50 five-minute writes, and $20 one-hour writes per million tokens. Anthropic says the full 1M context remains at standard pricing; Astra uses higher prices once input passes 272K tokens.


Read the full GPT-6 Astra pricing breakdown or compare it with our Claude Fable pricing guide. Provider list prices do not automatically equal GlobalGPT credits or compatibility-layer billing.
Five matched API tests
We sent the same task to each model ID through the same OpenAI-compatible endpoint. Tests 1-4 allowed up to 2,000 output tokens. Test 5 used 1,200 for both after the gateway dropped longer non-streaming requests around 30 seconds. Every score uses five rules defined before testing. A blank result receives no credit for invisible work.
Reasoning: SaaS cost decision
Astra completed the financial model; Fable stopped during assumptions.
View exact task
HTTP 200 · 28.98s · 242 input · 1,427 completion · score 10/10
HTTP 200 · 26.01s · 357 input · 2,000 completion · score 1/10
Writing: product launch edit
Both produced usable copy, but Fable introduced details absent from the notes.
View exact task
HTTP 200 · 15.47s · 165 input · 500 completion · score 10/10
HTTP 200 · 26.01s · 263 input · 1,881 completion · score 8/10
Coding: TypeScript concurrency
Astra returned a strong diagnosis and partial tests; Fable returned no visible answer in this route.
View exact task
HTTP 200 · 41.54s · 181 input · 2,000 completion · score 9/10
HTTP 200 · 29.44s · 277 input · 2,000 completion · score 0/10
Long context: planted amendment
Both found and quoted the controlling Section 417 amendment.
View exact task
HTTP 200 · 14.96s · 99,495 input · 244 completion · score 10/10
HTTP 200 · 22.24s · 295,912 input · 1,053 completion · score 10/10
Strategy: 90-day GTM plan
Astra began a grounded plan but was truncated; Fable returned no visible answer.
View exact task
HTTP 200 · 34.27s · 210 input · 1,200 completion · score 4/10
HTTP 200 · 21.09s · 338 input · 1,200 completion · score 0/10
คุณควรเลือกรุ่นไหนดี?
- Reasoning and operational decisions: Astra was much more complete in this run.
- Writing: both were usable; Astra was tighter to source notes, while Fable sounded polished but invented interface specifics.
- การเขียนโค้ด: Astra produced the stronger visible diagnosis. Compare broader patterns in our Claude vs ChatGPT coding guide.
- Long documents: both found the contradiction exactly. Token accounting differed dramatically, so test cost with your own documents.
- Agentic strategy: neither completed the constrained task within the final cap; Astra still returned usable partial work.



For another benchmark frame, see GPT-6 Astra vs GPT-5.6 Sol หรือ Claude Fable 5 vs GPT-5.5.
How to compare both in GlobalGPT
GlobalGPT exposes separate landing routes for both models. Use the same prompt, output constraint, and source material, then judge visible correctness before style. Record latency and token usage when the interface or API returns them. For long documents, measure each route independently because identical text may tokenize differently.


คำถามที่มักถูกถาม
Is GPT-6 Astra cheaper than Claude Fable 5.1?
Their base input and output list prices are the same. Cache-hit pricing and long-context rules differ, while GlobalGPT billing may use separate credits.
รุ่นใดมีหน้าต่างบริบทที่ใหญ่กว่า?
GPT-6 Astra lists 1.05M tokens and Claude Fable 5.1 lists 1M. Both list a 128K maximum output.
Which was better for coding?
GPT-6 Astra produced the stronger visible answer in our single TypeScript test. Fable returned no visible content through this compatibility route, so this is not a provider-native verdict.
Which was better for long-context retrieval?
They tied at 10/10, locating and quoting the same planted amendment. Fable reported nearly three times as many input tokens for the identical dossier.
Why did Fable score lower?
Several Fable calls consumed completion tokens but returned truncated or blank visible content. That may be a compatibility-layer or output-serialization issue.
Can I use both models in GlobalGPT?
Yes. Both dedicated GlobalGPT routes were live when checked on September 8, 2026.
คำตัดสินสุดท้าย
GPT-6 Astra is the safer default from this test set: it returned more complete, usable work and finished with 43/50 versus 19/50. Claude Fable 5.1 still matched Astra on the long-context accuracy task and produced solid marketing copy. Before rejecting Fable, repeat the tests through your production endpoint; two blank outputs are as much a warning about integration behavior as model behavior.



