Claude Fable 5.1 vs Gemini 4 Argon

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

Estimate monthly cost for these models
Metric
Claude Fable 5.1Anthropicanthropic/claude-fable-5.1
Gemini 4 ArgonGooglegoogle/gemini-4-argon
Creator
Anthropic
Google
Released
Sep 1, 2026
Oct 13, 2026
Context window
1M
1.05M (best)
Max output
128K (best)
66K
Input / 1MLowest provider price
$10.00
$2.00 (best)
Output / 1MLowest provider price
$50.00
$10.00 (best)
Providers
1
2 (best)
IntelligenceArtificial Analysis index
47.0
50.4 (best)
Accepts
Text, Image, Files
Text, Image, Audio, Video, Files
Produces
Text
Text
Tool calling
Yes
Yes
Structured output
Yes
No
Reasoning
Yes
No

Claude Fable 5.1 vs Gemini 4 Argon: summary

Claude Fable 5.1 and Gemini 4 Argon 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 5.1, from Anthropic, has a 1,000,000-token context window, costs $10.00/1M input and $50.00/1M output tokens and scores 47.0 on the Artificial Analysis Intelligence Index.

Gemini 4 Argon, from Google, has a 1,048,576-token context window, costs from $2.00/1M input and $10.00/1M output tokens across 2 providers and scores 50.4 on the Artificial Analysis Intelligence Index.

Gemini 4 Argon is the cheapest on input, 5× cheaper than the next model, Gemini 4 Argon has the largest context window and Gemini 4 Argon scores highest for intelligence.

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-5.1", messages=[...]) # or client.chat.completions.create(model="google/gemini-4-argon", messages=[...])
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Benchmark scores sourced from ArtificialAnalysis