GLM-5.2 is now just 0.005 away from Fable-5 in visual spec-to-app development.
On VISTAโs latest C4 leaderboard:
๐ฅ Claude Code + Fable-5 โ 0.274
๐ฅ Claude Code + GLM-5.2 โ 0.269
๐ฅ Claude Code + Opus 4.8 โ 0.263
ใ Claude Code + Sonnet 4.6 โ 0.248
ใ Cursor + Composer 2.5 โ 0.212
ใ Codex + GPT-5.5 โ 0.205
The story is no longer just โwhich model writes better code.โ
For real app-building agents, performance is increasingly shaped by the full stack:
๐ง model
๐ ๏ธ harness
๐ tool loop
๐๏ธ visual understanding
โ๏ธ reasoning setup
The harness is becoming part of the model.
๐