Cohere's Rerank 5 adds passage-level Context Focus, and the Pro model ranked first on 39 of 46 retrieval datasets
AspireAI community · Cohere
Cohere released Rerank 5 in Pro and Fast tiers for enterprise retrieval, and its headline feature is Context Focus: one rerank call returns the most relevant passages inside each document instead of whole chunks, which the company says cuts LLM token cost with minimal loss in answer quality. On Cohere's own evaluation using its RCP-nDCG@10 methodology, Rerank 5 Pro ranked first on 39 of 46 composite datasets and at least second on 43, scoring 82.2 on BRIGHT (5.8 points above Voyage AI Rerank 3, 12.4 above its own Rerank 4 Pro) and leading the strongest external competitor by 1.6 points on ViDoRe V3, 1.8 on BEIR and 3.4 on nanoMTEB. Fast beat Voyage Rerank 3 Lite and both Qwen3-Reranker sizes on all four benchmarks, and Pro ranked first in 14 of 19 non-English languages. The models are generally available via the Cohere API, Model Vault, Microsoft Foundry and Amazon SageMaker, at $0.05 per million tokens for Pro and $0.02 for Fast. Caveat: these are vendor-run benchmarks on Cohere's own scoring methodology, so the ranking claims have not been independently reproduced.
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Two sparse-autoencoder analyses have resisted scaling: matching semantically similar features across layers, and compressing large feature circuits into interpretable supernodes. This paper argues both are the same underlying problem, estimating semantic distances between SAE features that sit on different activation manifolds. Its representation treats each feature not as a single decoder vector but as an activation-weighted distribution over the hidden states expressing it, projects those distributions into a shared reference space, and compares them with Wasserstein distance. The representation is proved invariant to activation rescaling and stable under perturbation, and recovers true matches under finite-sample margin conditions. Empirically it outperformed decoder-vector and LLM-based baselines and captured subtle functional distinctions between related features, and it compressed large feature circuits into interpretable supernodes automatically. The limitation is that this is interpretability tooling: the paper demonstrates better feature matching and circuit compression, not that downstream interpretability claims become more accurate.