MetaUnited States· released Sep 2026

Muse Spark 1.3

Name: Muse Spark 1.3
Author: Meta

Provisional: 1 comparable test so far. Ranked once it reaches 6 across 3 counting categories.

Meta, United States. One of 4 models from this lab on the Index.

Third-party publishedLow confidence (thin coverage)

Snapshot September 8, 2026

OpenCharts Index

53.6

Provisional: not enough comparable tests or counting categories to rank yet · 1 comparable tests · 0 counting categories

Needs more results (0 of 8 so far)

Distance to today's frontier on the hardest tests. Not a measure of intelligence.

What it's known for

Muse Spark 1.3, in 1 result.

Its widest gap is on Code Arena (WebDev), 46.4% behind the best published result. No comparable results yet in reasoning, knowledge, math, agentic, multimodal, human preference and long context. Between 40% and 50% behind the best published results, on average.

Strongest category

No category counts yet: a category counts once it has more than one comparable test and the model has taken at least half of them. The scores it has are below.

Best single result

Code Arena (WebDev)

Build a web app from the same prompt as a rival model; real users vote blind on the result.

1,622

27% expected win rate against the board leader (1,797) · #9 of 86.

People judging finished apps side by side is the most honest measure of front-end quality.

Where it trails

Code Arena (WebDev)

Build a web app from the same prompt as a rival model; real users vote blind on the result.

1,622

46.4 points short of parity with the board leader (1,797) · #9 of 86.

People judging finished apps side by side is the most honest measure of front-end quality.

Not measured yet

No comparable result yet in these 7 categories. A blank is a blank, never a zero, and it does not lower the Index.

Reasoning
Knowledge
Math
Agentic
Multimodal
Human preference
Long context

Covered, but not averaged into the Index:

Coding1 of 7 tests · needs 4 · mean 53.6

Every score, with its source

See it at work

What Muse Spark 1.3 was asked to do, and how it did.

Every test it has taken, by category, with the kind of task it faced, who produced the number and where the result landed against the best published one. The examples are original and illustrative, never items from the datasets themselves.

Coding · mean 53.6 across 1 comparable test · not counted toward the Index yet (fewer than half the category's tests)

Code Arena (WebDev)Leaderboard

Build a web app from the same prompt as a rival model; real users vote blind on the result.

1,622

27% expected win rate against the board leader (1,797)
#9 of 86

xhigh · board 2026-09-05

Source: Arena

Every result is read against the best published one on its test: percent scores as a share of the best above chance, Arena ratings as the expected win rate against the board leader, open-ended values on a log scale. Sitting a harder exam never lowers a model. Every number links to the publisher that produced it.

Scores

Every test, every source

The best published run per benchmark, the raw value as the publisher reports it, who produced the number, how close it comes to the best published result on that test, and where the model sits among every model scored on it. Percent scores are read above chance, Arena ratings as a win rate against the board leader, open-ended values on a log scale. A test with too few models to compare against is shown but not counted.

Category means

Reasoning—
Knowledge—
Coding53.6 · 1/7
Math—
Agentic—
Multimodal—
Human preference—
Long context—

Mean · tests taken of the category's comparable tests. A faded category either rests on fewer than half of them or is a single-test category (marked “beside”), which is shown next to the Index and never averaged into it.

Code Arena (WebDev)LeaderboardCoding

1,622

27% expected win rate against the board leader (1,797)
91th percentile of 86

xhigh · board 2026-09-05

Source: Arena (LMArena) — Leaderboard Dataset

Top of the leaderboard