GLM-5.3 vs GPT-6 Astra vs Muse Spark 1.2

It is close. Our weighted score puts them within 3 points (Muse Spark 1.2 71/100, GPT-6 Astra 68/100, GLM-5.3 63/100), so choose by what matters most for your work: GPT-6 Astra for raw capability and Muse Spark 1.2 on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Muse Spark 1.2 is cheaper at $1.25 input / $4.25 output per million tokens (official Meta API price). GLM-5.3 costs $1.40 input / $4.40 output per million tokens (official Z.AI API price); GPT-6 Astra costs $10.00 input / $50.00 output per million tokens (official OpenAI API price). At a typical mix of three input tokens to one output token, that is $2.00 per million tokens for Muse Spark 1.2 versus $2.15 for GLM-5.3 (1.1× as much) and $20.00 for GPT-6 Astra (10× as much).

GPT-6 Astra scores higher on the Capabilities Index (ECI): GPT-6 Astra 169.1 (#1 of 165), GLM-5.3 156.2 (#33 of 165) and Muse Spark 1.2 155.2 (#38 of 165). Their confidence ranges do not overlap (165.9–174.3 vs 154.3–158.5), so the gap is a real one. On individual benchmarks: SimpleQA Verified — GPT-6 Astra 75.6%, Muse Spark 1.2 60.3%, GLM-5.3 41.0%.

There are no published SWE-bench Verified results for GLM-5.3, GPT-6 Astra and Muse Spark 1.2 yet, so there is no like-for-like coding score. On overall capability, GPT-6 Astra leads, which tends to carry over to coding, but test on your own codebase. All three support tool calling for agent workflows.

GPT-6 Astra and Muse Spark 1.2 have the largest context windows (1,050,000 and 1,048,576 tokens), against 1,000,000 for GLM-5.3. Maximum output per response: GLM-5.3 up to 131,072, GPT-6 Astra up to 128,000, Muse Spark 1.2 up to 131,072 tokens.

GLM-5.3 accepts text; GPT-6 Astra accepts text, images and PDFs; Muse Spark 1.2 accepts text, images, PDFs, audio and video. Muse Spark 1.2 handles the widest range of inputs.

GLM-5.3 publishes its weights and can be self-hosted; GPT-6 Astra and Muse Spark 1.2 is proprietary.

GPT-6 Astra is the newest, released Sep 4, 2026. GLM-5.3 came out Aug 14, 2026; Muse Spark 1.2 came out Aug 5, 2026. Knowledge cutoff: GPT-6 Astra Apr 30, 2026.

Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Nov 2, 2026.