MRCR 512K–1M
Meta scorecard. Claude Opus 5 is marked unavailable for this context band.
Meta's September 2 release targets long-horizon coding, browser, and desktop agents. Its launch scorecard reports 75.4% on DeepSWE v1.1, 98.1% retrieval across 512K to 1M tokens, and 20% fewer tool calls. Muse Spark 1.3 is available in the SPIRITT model picker for agentic apps and workflows.
Every original post remains. New official showcase posts add a rendering engine, a playable 3D kart racer, and a production-style guitar tuner, each built from a one-shot prompt.
The thing that surprised me most about Muse Spark was how many people were totally fine choosing the contributor tier to pay much (much) less for near frontier intelligence Can’t wait to see Muse Spark 1.3 usage! @alexandr_wang you’re moving fast!
— Tamir (@TamirSPIRITT) September 2, 2026
1/ today we’re releasing muse spark 1.3—available in muse code & the meta model api. this is our most capable model yet—frontier performance almost too cheap to meter. much stronger at agentic and coding with better usability. we think users will really notice the jump.
— Alexandr Wang (@alexandr_wang) September 2, 2026
Excited to announce Muse Spark 1.3, a strong agentic update to our Spark series. Muse Spark is a more proactive model, better for long-horizon work and real-world users. 1.3 is MSL’s 3rd launch in 3 days!!! Coding, voice, and agents 🚀🚀🚀
— Linda Gong (@lindugong) September 2, 2026
Meta Muse Spark 1.3 benchmarks are out! It's SOTA Long Context and DeepSWE v1.1!!!
— cheaty (@cheatyyyy) September 2, 2026
Meta Muse Spark 1.3 is live on OpenCode Zen! thanks @BennettBuhner for noticing this and posting about it!
— cheaty (@cheatyyyy) September 2, 2026
We’re excited to release Muse Spark 1.3 with improved performance on agentic and coding tasks, and a focus on real-world usability. Key capabilities: → Sustains longer-horizon work across multiple workflows in a single thread → More actively collaborates with users: it asks clarifying questions, flags when it's stuck, confirms before consequential actions → Better calibrated on its own limits instead of hallucinating outcomes → ~20% fewer tool calls and ~25% fewer tokens vs. Muse Spark 1.2 in internal comparisons
— AI at Meta (@AIatMeta) September 2, 2026
Muse Spark 1.3 is rolling out today with frontier performance almost too cheap to meter. This is the biggest jump we've made so far on coding and agentic work. Try it in Muse Code and our API. Next up 🍉 and Muse Spark open weights releases coming soon.
— Mark Zuckerberg (@finkd) September 2, 2026
Look at how good Muse Spark 1.3 Max is at 3D (its a ONE SHOT) Heres the link to the 3D model from the video: https://muse-spark-1-3-3d-preview.spiritt.app/ You can try Muse Spark 1.3 Max on SPIRITT Workspaces with full agentic capabilities https://spiritt.ai/models/muse-spark-1-3
— Tamir (@TamirSPIRITT) September 5, 2026
Meta has released Muse Spark 1.3, their fourth Muse Spark model release in five months. Muse Spark 1.3 (max), which is in limited preview for Meta’s partners, scores 62 on the Artificial Analysis Intelligence Index, behind only Claude Fable 5.1 and Claude Opus 5. The variant available now, Muse Spark 1.3 (xhigh), scores 61 and ties with GPT-5.6 Sol (max) and Grok 4.6 (high). Both variants’ gains come primarily from improvements in agentic work and scientific capabilities Muse Spark 1.3 (xhigh) enters the Artificial Analysis Intelligence Index at 61, up 4 points from Muse Spark 1.2 (57, August) and 8 points from Muse Spark 1.1 (53, July). It enters tied with GPT-5.6 Sol (max), Grok 4.6 (high), and Claude Opus 5 (high), and behind Claude Fable 5.1 (max, 66), Claude Opus 5 (max, 63), and Claude Fable 5 (max, 62) Muse Spark 1.3 (max), which is in a limited preview stage, lands at 62. This higher index score is enabled by gains vs. Muse Spark 1.3 (xhigh) in Tau3-Bench Banking (52% vs. 47%) and GDPval-AA v2 (1,754 Elo vs. 1,709). Muse Spark 1.3 (max) is second only to Claude’s Fable and Opus variants in total score Congratulations to @AIatMeta, @finkd, and @alexandr_wang on the release! Key Takeaways: ➤ Continued improvement on agentic knowledge work tasks. At the launch of Muse Spark 1.2, we noted its significant gains in agentic knowledge work performance vs. Muse Spark 1.1. The latest iteration continues this trend, with Muse Spark 1.3 (xhigh) demonstrating a notable 12-point gain vs. Muse Spark 1.2 in Tau3-Bench Banking (35% to 47%), a 5-point gain in Terminal-Bench 2.1 (80% to 85%), and a new GDPval-AA v2 Elo of 1709 against its predecessor’s 1615. Muse Spark 1.3 (max) improves further on Tau3-Bench Banking (52%) and GDPval-AA v2 (1,754 Elo). This Tau3-Bench Banking score is #1 among all models. Muse Spark 1.3 (max) achieves these higher agentic work scores by using more turns and total reasoning tokens, reasoning 62% more on GDPval-AA v2 and 28% more on Tau3-Bench Banking compared to Muse Spark 1.3 (xhigh) ➤ The lowest cost per task for any model at 59+ on the Artificial Analysis Intelligence Index. Muse Spark 1.3 (xhigh) costs $0.55 per Intelligence Index task at Meta's unchanged $1.25/$4.25 per 1M token pricing ($0.15 for cached input), with its peers GPT-5.6 Sol (max) and Grok 4.6 (high) costing $0.95 and $0.94 respectively, a 70%+ premium. This places Muse Spark 1.3 (xhigh) on the Pareto frontier for Intelligence vs. Cost per Task. Its cost per task is higher than Muse Spark 1.2 ($0.40 per task), driven by ~57% more input tokens per task on agentic evaluations, with output tokens up only ~8%. Pricing for Muse Spark 1.3 (max) is not yet publicly available ➤ Scientific Reasoning results rose across the board, led by CritPt. CritPt was the standout non-agentic score gain vs. Muse Spark 1.2, with a material +8 points for the xhigh variant (18% to 26%), and GPQA Diamond achieved +4 points (90% to 94%), while Humanity’s Last Exam and SciCode each gained a more modest 2-3 points (45% to 47% and 56% to 59%, respectively). Muse Spark 1.3 (max) achieved roughly similar scores to the xhigh variant, gaining 2 points in Humanity’s Last Exam, tying on GPQA Diamond, and losing a point on CritPt vs. Muse Spark 1.3 (xhigh) ➤ Minor regressions in only two evaluations. Both Muse Spark 1.3 (xhigh) and Muse Spark 1.3 (max) dropped 4 points in AA-LCR (83% to 79%) when compared to Muse Spark 1.2, and AA-Omniscience (Accuracy) fell 3 points for xhigh and 1 point for max. The drops in AA-Omniscience (Accuracy) are due to a higher abstention rate (not answering questions when unsure), which also lowered the hallucination rate for Muse Spark 1.3 (xhigh) Other model details (xhigh variant): ➤ Context window: 1M tokens, unchanged from Muse Spark 1.2 ➤ Pricing: unchanged from Muse Spark 1.2: $1.25/$4.25 per 1M input/output tokens, with cache hits discounted to $0.15 per 1M ➤ Input modalities: text, image, video ➤ Availability: Meta's first-party API and Muse Code
— Artificial Analysis (@ArtificialAnlys) September 2, 2026
Meta's Muse Spark 1.3 (max), which is in limited preview for Meta's partners, scores 68 on the Artificial Analysis Coding Agent Index in the Muse Code harness, #2 behind only Claude Opus 5 (xhigh) in Claude Code. The variant available now, Muse Spark 1.3 (xhigh), scores 64 and costs the least per task of any agent above a 60 index score Muse Spark 1.3 (xhigh) enters the Artificial Analysis Coding Agent Index at 64 in Muse Code, up 2 points from Muse Spark 1.2 (62, August). It enters level with Grok 4.5 (high) in Grok Build (64) and behind GPT-5.6 Sol (max) in Codex (65). At $1.72 per task, it costs the least of any agent above a 60 index score, around a fifth of the cost of Claude Opus 5 (xhigh) in Claude Code ($8.17) Muse Spark 1.3 (max), which is in a limited preview stage, lands at 68 in Muse Code. It enters behind only Claude Opus 5 (xhigh) in Claude Code (68), and ahead of Claude Fable 5 (max) in Claude Code (67) and GPT-5.6 Sol (max) in Codex (65). Muse Spark 1.3 (max) is excluded from cost comparisons as Meta has not announced pricing for the limited release Claude Fable 5.1 results are in progress and will be added when complete. Congratulations @AIatMeta, @finkd, and @alexandr_wang on this result!
— Artificial Analysis (@ArtificialAnlys) September 3, 2026
Meta Muse Spark 1.3 is now free on OpenCode
— OpenCode (@opencode) September 3, 2026
Muse Spark 1.3 is now available in Muse Code and Meta Model API. It’s tuned for the agentic builds developers actually ship, including long-running, multi-agent workflows. 🧵👇(1/4)
— Meta for Developers (@MetaforDevs) September 2, 2026
Muse Spark 1.3 with max reasoning is now available on Muse Code and Meta Model API. Developers can build with frontier performance without the frontier prices. We thought showing would be better than telling, and encouraged our friends in Meta Superintelligence Labs to come up with a few demos. One-shot prompt: Build a rendering engine from scratch in C that writes pixels directly, scales from simple primitives to complex scenes, and culminates in a striking lighting demo. Check out the rest 👇🏻(1/4)
— Meta for Developers (@MetaforDevs) September 4, 2026
One-shot prompt: make me a 3D kart racing game that I can play in the browser. Make the graphics look polished, they don’t need to be 100% realistic. (2/4)
— Meta for Developers (@MetaforDevs) September 4, 2026
One-shot prompt: Build an insanely accurate and beautiful guitar tuner, with extremely good pitch detection, support for various tuning and much more. It should be a calm, minimal, yet beautiful design which looks simple on surface but is very powerful underneath. Use any library, etc, you want to make this the perfect, premium, production ready app. (3/4)
— Meta for Developers (@MetaforDevs) September 4, 2026
Meta's scorecard shows a broad step up from Muse Spark 1.2. Independent testing now confirms a frontier-adjacent xhigh model, while also clarifying the limits of the max configuration.
Meta positions Muse Spark 1.3 as a major upgrade for coding, UI understanding, browser use, desktop automation, and multi-hour agentic workflows. The company reports more reliable tool use, better task planning, 20% fewer tool calls, and 25% fewer tokens than Muse Spark 1.2 in internal comparisons.
Meta's launch scorecard reports 75.4% on DeepSWE v1.1, 59.4% on SWEAtlas CodeBase QnA, 66.9% on OSWorld 2.0, and 98.1% on MRCR's 512K-to-1M-token band. Those are vendor-compiled results drawn from a mix of official leaderboards, self-reported comparator scores, and Meta-run evaluations under the linked methodology.
Artificial Analysis independently measured the available xhigh configuration at 61 on its launch-day Intelligence Index and 64 on its Coding Agent Index. The max configuration reached 62 and 68 respectively, but remained in limited partner preview and did not have public pricing at verification time.
Muse Spark 1.3 is available in the SPIRITT model picker. Select it inside a fully equipped workspace to build agentic apps and workflows with browser, terminal, files, tools, memory, and integrations.
Meta launch scorecard. Muse Spark 1.3 max at 1,754 improves 139 points over 1.2 and sits between the displayed GPT-5.6 Sol and Claude Opus 5 results.
All 1.3 figures below come from Meta's launch scorecard and methodology. They are not independent SPIRITT reruns.
Meta scorecard. Claude Opus 5 is marked unavailable for this context band.
Meta scorecard. The 75.4% result is 20.4 points above Muse Spark 1.2.
Meta scorecard. Higher is better.
Meta scorecard. Muse Spark 1.3 ties the displayed GPT-5.6 Sol result.
Meta scorecard. Muse Spark 1.3 nearly matches the strongest displayed result but does not lead.
Meta scorecard. Muse Spark 1.3 is 0.8 points behind the displayed leader.
Meta scorecard. Strong absolute result, but behind both displayed frontier comparators.
Meta scorecard. Muse Spark 1.3 improves sharply over 1.2 but remains just behind the displayed leader.
Vendor source: Meta's September 2 Muse Spark 1.3 launch scorecard and linked multimodal evaluation methodology. Meta selects the highest comparable published score for each system from official leaderboards, self-reported results, or its own runs, so every chart remains labeled vendor-compiled. Independent context: Artificial Analysis's September 2 and 3 evaluations of the xhigh and limited max configurations. Evaluate the released configuration on your own workloads before production use.
Choose Muse Spark 1.3 in the picker, then build the agentic workflow
Open a workspace and land in a fully equipped cloud computer: browser, files, terminal, integrations, and memory. No local setup. No thin chat box pretending to be an agent.

Open the SPIRITT model picker and select Muse Spark 1.3. Then give it the tools and acceptance path for a real coding, browser, or long-horizon agent task.

Tell it what to ship or what to run. Muse Spark 1.3 can code, call tools, drive the browser, coordinate multi-step work, and keep going while you step away. The point is not another chat window. It is an agentic environment where Muse Spark 1.3 actually does the job.

Open a SPIRITT Workspace, choose Muse Spark 1.3 in the model picker, and turn the release into a working agentic app or workflow.