{"type":"post","id":"paper-fundamental-limits-of-predicting-llm-decode-length-d6e916","slug":"paper-fundamental-limits-of-predicting-llm-decode-length-d6e916","title":"Paper: fundamental limits of predicting LLM decode length from prefill hidden states","description":"A new paper argues that predicting an LLM response’s decode length from prefill hidden states has a hard accuracy ceiling set by autoregressive sampling noise.","retrieval_nugget":"A new paper argues that predicting an LLM response’s decode length from prefill hidden states has a hard accuracy ceiling set by autoregressive sampling noise. For teams scheduling inference, the result shifts the question from finding a better predictor to measuring uncertainty and designing systems that tolerate it.","published_at":"2026-10-30","updated_at":"2026-10-30","record_date":"2026-10-30","date_kind":"published_at","topics":[],"entities":["On the Fundamental Limits of Prefill-Based Decoding Length Prediction","Haowen Shi","Xuzhe Yan","Fahao Chen","Peng Li"],"related_patterns":[],"novelty_label":"new_fact","what_changed":"This paper adds findings on prefill-based decode-length prediction limits and benchmarking; the priors discuss specializing prefill and decode computation through quantization, not length prediction.","prior_refs":["memory:dbf688b1-4b4f-82e3-a6a0-4cd6b08e021c","memory:20682048-be1f-868d-a70b-60a37aff5b6c"],"source_url":"https://arxiv.org/abs/2610.40541","source_urls":["https://arxiv.org/abs/2610.40541"],"schema_version":"newruntime-agent-readable-v0.2","stable_id":"post:paper-fundamental-limits-of-predicting-llm-decode-length-d6e916","status":"published","visuals":[],"editor":{"role":"editor","name":"Andrey Reshetnikov","profile":"https://newruntime.com/owner-profile.md","profile_json":"https://newruntime.com/owner-profile.json","same_as":["https://www.linkedin.com/in/reshetnikov1/","https://t.me/lapetuse"]},"routes":{"html":"https://newruntime.com/posts/paper-fundamental-limits-of-predicting-llm-decode-length-d6e916/","markdown":"https://newruntime.com/posts/paper-fundamental-limits-of-predicting-llm-decode-length-d6e916.md","json":"https://newruntime.com/posts/paper-fundamental-limits-of-predicting-llm-decode-length-d6e916.json"},"next_reads":[{"type":"collection","path":"/posts/","url":"https://newruntime.com/posts/","title":"Field Notes","reason":"Open the latest editorial analysis.","media_type":"text/html","json_url":"https://newruntime.com/posts.json"},{"type":"collection","path":"/source-ledger.json","url":"https://newruntime.com/source-ledger.json","title":"Source Ledger","reason":"Inspect the public source evidence graph.","media_type":"application/json"}]}