Bijan Bowen tests Solar Pro 4, a mixture-of-experts model from South Korean lab Upstage with a large context window and support for English, Korean and Japanese. The model is available through hosted access rather than downloadable open weights.
Solar Pro 4 is inconsistent on browser control, games, three-dimensional scenes and front-end design. Bijan Bowen repeatedly sees incomplete or visually weak results, although the model can recover enough to produce a functional interface after several iterations.
The strongest demonstration is a C++ debugging task. Instead of making one speculative rewrite, Solar Pro 4 creates small smoke tests, checks individual components, identifies the failing assumption and advances step by step. Bijan Bowen values this method even though the model's overall coding quality remains below stronger alternatives.
Creative roleplay and simulation tasks also reveal a distinctive, assertive personality. Bijan Bowen concludes that Solar Pro 4 is not a leading general coding model, but its iterative troubleshooting behavior offers a useful example of how model quality can depend on process as much as the first answer.
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