Mycelium Benchmark: Claude Fable 5

Same zero-shot prompt, new model, one twist: this time the model under test ran the benchmark on itself. From inside Claude Code, Claude Fable 5 generated the SVG and wrote this post. The prompt, as always: “Generate an animated SVG of a mycelium network connecting three trees, with nutrients flowing through it.”

Like Opus 4.8, it bound every nutrient to an <mpath> pointing at the threads it drew, so nothing drifts in open space. It also took a swing at the blandness I called out in Opus: the center tree is a mother tree feeding a sapling on the right. Amber sugars flow out through her roots, cyan minerals flow back through a deep arc and a junction hub, and the sapling’s small canopy brightens as the food arrives. Keep in mind that the model which drew this also wrote the paragraph praising it. Judge for yourself below.