Which is cheaper, Claude Fable 5.1 and Inkling Small?

Inkling Small has the lowest input price. Per 1M input tokens: Claude Fable 5.1 from $10.00 and Inkling Small from $0.45.

Which has the larger context window, Claude Fable 5.1 and Inkling Small?

Claude Fable 5.1 has the largest context window: Claude Fable 5.1 1,000,000 tokens and Inkling Small 524,288 tokens.

Which is smarter, Claude Fable 5.1 and Inkling Small?

Claude Fable 5.1 scores highest on the Artificial Analysis Intelligence Index: Claude Fable 5.1 47.2 and Inkling Small 12.9.

Can I switch between Claude Fable 5.1 and Inkling Small 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-5.1, thinkingmachines/inkling-small).

Claude Fable 5.1 vs Inkling Small

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

Estimate monthly cost for these models

Claude Fable 5.1 Anthropicanthropic/claude-fable-5.1

Inkling Small Thinking Machinesthinkingmachines/inkling-small

Creator

Anthropic

Thinking Machines

Released

Sep 1, 2026

Jul 30, 2026

Context window

524K

Max output

128K

262K

Input / 1MLowest provider price

$10.00

$0.45

Output / 1MLowest provider price

$50.00

$1.20

Providers

IntelligenceArtificial Analysis index

47.2

12.9

Accepts

Text, Image, Files

Text, Image, Audio

Produces

Text

Tool calling

Yes

Structured output

Yes

Reasoning

Yes

Claude Fable 5.1 vs Inkling Small: summary

Claude Fable 5.1 and Inkling Small 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 47.2 on the Artificial Analysis Intelligence Index.

Inkling Small, from Thinking Machines, has a 524,288-token context window, costs $0.45/1M input and $1.20/1M output tokens and scores 12.9 on the Artificial Analysis Intelligence Index.

Inkling Small is the cheapest on input, 22× cheaper than the next model, Claude Fable 5.1 has the largest context window and Claude Fable 5.1 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="thinkingmachines/inkling-small", messages=[...])

Full API docs

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More comparisons

Benchmark scores sourced from ArtificialAnalysis