Which has the larger context window, Claude Fable 5 and GPT-6 Astra?

GPT-6 Astra has the largest context window: Claude Fable 5 1,000,000 tokens and GPT-6 Astra 1,050,000 tokens.

Which is better for coding, Claude Fable 5 and GPT-6 Astra?

GPT-6 Astra scores highest on the Artificial Analysis Coding Index: Claude Fable 5 76.5 and GPT-6 Astra 77.1.

Which is smarter, Claude Fable 5 and GPT-6 Astra?

GPT-6 Astra scores highest on the Artificial Analysis Intelligence Index: Claude Fable 5 49.6 and GPT-6 Astra 50.9.

Can I switch between Claude Fable 5 and GPT-6 Astra without changing my code?

Yes. All of them are served through FastRouter's OpenAI-compatible API, so switching is a change of the model parameter (anthropic/claude-fable-5, openai/gpt-6-astra).

Claude Fable 5 vs GPT-6 Astra

Side-by-side pricing per provider, context window, benchmark scores and speed, all on one OpenAI-compatible API.

Claude Fable 5 Anthropicanthropic/claude-fable-5

GPT-6 Astra OpenAIopenai/gpt-6-astra

Creator

Anthropic

OpenAI

Released

Jun 9, 2026

Sep 4, 2026

Context window

1.05M

Max output

128K

Input / 1MLowest provider price

$10.00

Output / 1MLowest provider price

$50.00

Providers

IntelligenceArtificial Analysis index

49.6

50.9

CodingArtificial Analysis index

76.5

77.1

LatencyMedian time to first token

14s

—

ThroughputMedian tokens per second

<1 t/s

—

Accepts

Text, Image, Files

Text, Image

Produces

Text

Tool calling

Yes

Structured output

Yes

Reasoning

Yes

Claude Fable 5 vs GPT-6 Astra: summary

Claude Fable 5 and GPT-6 Astra are both available through FastRouter's OpenAI-compatible API, so switching between them is a change of model id, not a new integration.

Claude Fable 5, from Anthropic, has a 1,000,000-token context window, costs $10.00/1M input and $50.00/1M output tokens and scores 49.6 on the Artificial Analysis Intelligence Index.

GPT-6 Astra, from OpenAI, has a 1,050,000-token context window, costs $10.00/1M input and $50.00/1M output tokens and scores 50.9 on the Artificial Analysis Intelligence Index.

GPT-6 Astra has the largest context window, GPT-6 Astra scores highest for intelligence and GPT-6 Astra leads on coding.

Switch with one line

client = OpenAI(base_url="https://api.fastrouter.ai/api/v1", api_key="<FASTROUTER_API_KEY>") client.chat.completions.create(model="anthropic/claude-fable-5", messages=[...]) # or client.chat.completions.create(model="openai/gpt-6-astra", messages=[...])

Full API docs

Frequently asked questions

More comparisons

Benchmark scores sourced from ArtificialAnalysis