Hackathon knowledge base

What this is for: reading machine-learning papers about large language models (LLMs) is easier when every term has one fixed meaning. Every underlined term links to the glossary. Abbreviations are spelled out at first use on each page.

The steering code we are using (SafeTune)

SafeTune is Lexsi Labs' library for auditing and repairing safety behaviour in fine-tuned models. Its steering methods live in one folder. The one we use is Conditional Activation Steering (CAST), which adds a behaviour vector only when a condition vector fires. Its behaviour vector comes from Contrastive Activation Addition (CAA). Explanation: steering §10.

Note: SafeTune's code and docs credit CAST to "Wu et al." The paper on arXiv (2409.05907) is by Bruce W. Lee, Inkit Padhi and colleagues at IBM Research. IBM's original library: IBM/activation-steering. Line numbers are for commit 3901a9f (3 November 2026); the main links follow later changes.

Lexsi Labs tools

• SafeTune · docsAuditing and repairing safety drift in fine-tuned models: steering, unlearning, hardening.
• AlignTune · docsModular toolkit for post-training alignment, such as preference training.
• AuditKIT · docsOne library for benchmark, judge, red-team, security and performance evaluation.
• CircuitKIT · docsDiscover, evaluate and intervene on circuits in transformer models.
• CuratorKIT · docsData curation and synthetic data generation for post-training.
• AgentTune · docsReinforcement-learning trainer for tool-calling agents, plus a build, collect, evaluate, train pipeline.
• DLBacktrace · docsAn explainability technique for deep-learning models of any type.
• All Lexsi Labs repositories

Hackathon and models

• hackathon.lexsi.aiThe event site: rules, dates, tracks.
• Aya Expanse 8B (CohereLabs/aya-expanse-8b)Cohere Labs' multilingual chat model, 8 billion parameters. Access is gated: accept the terms on Hugging Face first.
• Tiny Aya collection · tiny-aya-globalSmaller multilingual models, about 3.3 billion parameters. The collection also has base, regional and "thinker" variants. Gated.