Sonoma Sky Alpha

A cloaked model OpenRouter ran in September 2025 with a two million token context. It was later revealed as the reasoning variant of xAI's Grok 4 Fast, and the alpha endpoint has since been retired.

Provider: OpenRouter
Released: 2025-09-05
Size: XLARGE
Free API (OpenRouter): No
Per 1M tokens: $0.00 in · $0.00 out
Estimated tab: ~$0.00; Visible-output estimate. Thinking may cost extra.

Free API availability

No free endpoint for Sonoma Sky Alpha was found in Rival’s OpenRouter listings. Other providers or chat apps may have separate free offers.

Provider data: 9 Sep 2026OpenRouter usage limits

View API options

Get API accessProvider and language code samples

Provider

fromimport openai  OpenAI

client = OpenAI(
"https://openrouter.ai/api/v1"    base_url=,
"$OPENROUTER_API_KEY"    api_key=,
)

response = client.chat.completions.create(
"openrouter/sonoma-sky-alpha"    model=,
"role""user""content""Hello!"    messages=[{: , : }],
)
print(response.choices[0].message.content)

Set OPENROUTER_API_KEY with your OpenRouter API key from openrouter.ai/keys.

Deep analysisPsychometrics, taste index, writing DNA

SubjectiveBench

Taste Index

Across 35 scored outputs

How this is measured →

160.16xFloor

0100headroom →

Taste is judged on an uncapped scale, originality first. The space past 100 is craft today's models rarely reach.

Craft26

Originality11

Plays it safe

share of outputs that are the default answer

86%

Writing DNA

Stylometric Fingerprint

Based on 14 text responses

Tick = global average

Vocabulary Diversity62%

Unique words vs. total words. Higher = richer vocabulary.

Sentence Length15.8 words

Average words per sentence.

Hedging0.41

"Might", "perhaps", "arguably" per 100 words.

Bold Formatting1.6

**Bold** markers per 1,000 characters.

List Usage2.8

Bullet and numbered list items per 1,000 characters.

Section Structure1.42

Markdown headings per 1,000 characters.

Emoji Usage0.13

Emoji per 1,000 characters.

Transitions0.06

"However", "moreover", "furthermore" per 100 words.

Opening Habits

Consistency

74%

Across 14 responses

Model Responses

35 outputs · generated before accounting joined the chat

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RANKINGS

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Compare Sonoma Sky Alpha

Alternatives to Sonoma Sky Alpha

Sonoma Sky Alpha

Free API availability

Taste Index

Stylometric Fingerprint

Model Responses

Sonoma Sky Alpha vs GPT-5

Best AI for Creative Writing