← Search

Xiang Lisa Li

12 accepted papers

2025

Auditing Prompt Caching in Language Model APIs

ICML 2025poster

Prompt caching in large language models (LLMs) results in data-dependent timing variations: cached prompts are processed faster than non-cached prompts. These timing differences introduce the risk of side-channel timing attacks. For example, if the cache is shared across users, an attacker could ide…

2025

AutoBencher: Towards Declarative Benchmark Construction

ICLR 2025poster

We present AutoBencher, a declarative framework for automatic benchmark construction, and use it to scalably discover novel insights and vulnerabilities of existing language models. Concretely, given a few desiderata of benchmarks (e.g., question difficulty, topic salience), we operationalize each d…

Cited by 0SourcePDFScholar
2025

Eliciting Language Model Behaviors with Investigator Agents

ICML 2025poster

Language models exhibit complex, diverse behaviors when prompted with free-form text, making it hard to characterize the space of possible outputs. We study the problem of behavioral elicitation, where the goal is to search for prompts that induce specific target behaviors (e.g., hallucinations, har…

Cited by 3SourcePDFScholar
2025

s1: Simple test-time scaling

EMNLP 2025

Test-time scaling is a promising new approach to language modeling that uses extra test-time compute to improve performance. Recently, OpenAI’s o1 model showed this capability but did not publicly share its methodology, leading to many replication efforts. We seek the simplest approach to achieve te

2024

Benchmarking and Improving Generator-Validator Consistency of Language Models

ICLR 2024poster

As of September 2023, ChatGPT correctly answers “what is 7+8” with 15, but when asked “7+8=15, True or False” it responds with “False”. This inconsistency between generating and validating an answer is prevalent in language models (LMs) and erodes trust. In this paper, we propose a framework for mea…

Cited by 29SourcePDFScholar
2024

On the Learnability of Watermarks for Language Models

ICLR 2024poster

Watermarking of language model outputs enables statistical detection of model-generated text, which can mitigate harms and misuses of language models. Existing watermarking strategies operate by altering the decoder of an existing language model. In this paper, we ask whether language models can dir…

2023

Contrastive Decoding: Open-ended Text Generation as Optimization

ACL 2023long

Given a language model (LM), maximum probability is a poor decoding objective for open-ended generation, because it produces short and repetitive text. On the other hand, sampling can often produce incoherent text that drifts from the original topics. We propose contrastive decoding (CD), a reliable…

2023

TempLM: Distilling Language Models into Template-Based Generators

ACL 2023findings

While pretrained language models (PLMs) have greatly improved text generation, they have also been known to produce unfaithful or inappropriate content. In contrast, classic template-based systems provide strong guarantees of faithfulness at the cost of fluency. We propose TempLM, which achieves the…

2022

Diffusion-LM Improves Controllable Text Generation

NeurIPS 2022accept

Controlling the behavior of language models (LMs) without re-training is a major open problem in natural language generation. While recent works have demonstrated successes on controlling simple sentence attributes (e.g., sentiment), there has been little progress on complex, fine-grained controls (…

2020

Specializing Word Embeddings (for Parsing) by Information Bottleneck (Extended Abstract)

IJCAI 2020poster

Pre-trained word embeddings like ELMo and BERT contain rich syntactic and semantic information, resulting in state-of-the-art performance on various tasks. We propose a very fast variational information bottleneck (VIB) method to nonlinearly compress these embeddings, keeping only the information th…

Cited by 0SourcePDFScholar