Climbmix Agent Run Mar 19 2026

Autonomous agent run on climbmix-400b-shuffle (Karpathy's default web crawl dataset) using the headless experiment runner. The agent ran 101 experiments over ~9 hours but found the configuration near-optimal — only 1 experiment was kept, improving val_bpb by just 0.08%.

This run started from an already partially-optimized baseline (AR=32, MATRIX_LR=0.0435) inherited from prior runs on the same branch, which explains the exceptionally tight margin for improvement.

Climbmix Agent Run — Mar 19, 2026

The baseline inherited optimizations from prior runs on this branch:

ASPECT_RATIO = 32 # ↓ from 64 (prior optimization)
MATRIX_LR = 0.0435 # ↑ from 0.04 (prior optimization)
WEIGHT_DECAY = 0.2 # Default
WARMDOWN_RATIO = 0.5 # Default
EMBEDDING_LR = 0.6 # Default
UNEMBEDDING_LR = 0.004 # Default
SCALAR_LR = 0.5 # Default
ADAM_BETAS = (0.8, 0.95) # Default

Only one experiment improved on the baseline:

The 0.08% improvement across 101 experiments is the smallest gain in any agent run to date. This indicates the starting configuration was already close to the local optimum for climbmix data on this hardware. For comparison:

11 experiments crashed (10.9% crash rate) — all from batch size modifications:

The agent repeatedly tried DEVICE_BATCH_SIZE changes (9 attempts) despite consistent crashes. Only the default batch size (and small reductions to 1–4) avoided crashing. This suggests the MLX backend has strict alignment requirements for batch dimensions.

The agent explored nearly every parameter category without finding improvements:

The distribution chart shows most experiments clustered between 1.30–1.33, with the baseline and best nearly overlapping. No experiment came close to the baseline other than exp84, confirming the parameter space around this configuration is a plateau.

• Branch: autoresearch/mar19-climbmix
• Agent: Claude Sonnet (headless runner)
• Date: March 19, 2026