Muse Spark 1.3

Meta's multimodal reasoning model for long-running agent and coding workflows. It tracks state across extended tasks, works through conflicting inputs and asks for confirmation when needed, with a 1M-token context window and concise execution. Access is restricted to adults.

Provider: Meta AI
Released: 2026-09-02
Size: LARGE
Free API (OpenRouter): No
Per 1M tokens: $1.25 in · $4.25 out
Rival’s tab: $1.45; 58/58 receipts survived

Free API availability

No free endpoint for Muse Spark 1.3 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(
"meta/muse-spark-1.3"    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

Writing DNA

Stylometric Fingerprint

Based on 27 text responses

Tick = global average

Vocabulary Diversity59%

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

Sentence Length13.9 words

Average words per sentence.

Hedging0.28

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

Bold Formatting2.6

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

List Usage2.3

Bullet and numbered list items per 1,000 characters.

Section Structure0.48

Markdown headings per 1,000 characters.

Emoji Usage0.00

Emoji per 1,000 characters.

Transitions0.02

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

Opening Habits

Consistency

82%

Across 27 responses

Favorites

Movie

Casablanca

19438.1

Album

Abbey Road

The Beatles

Book

Dune

Frank Herbert

City

Tokyo

Japan

Game

Minecraft

Action, Arcade4.4

Model Responses

53 outputs · $1.43 tracked across 53 receipts

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Stylometric Fingerprint

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Muse Spark 1.3 vs Ox Alpha

Best AI for Complex Reasoning