Evaluation LLM Infrastructure Production AI Systems

Choosing and Operating Tabular Models Inside AI Agents

AI agents that make decisions over structured data rely heavily on tabular learning models — but model choice has direct implications for agent reliability, routing, and operational behavior. In this benchmark, we evaluate 7 widely used tabular model families across 19 real-world datasets (~260k rows, 250+ features) to understand which models agents should invoke under different data regimes. Rather than focusing solely on average rank, we analyze win rates to capture dominance — a critical signal when agents must choose models dynamically at runtime. The results reveal that: Foundation models are most effective for agents operating with limited data XGBoost is the most reliable choice for large, numeric-heavy workloads Hybrid datasets at scale remain operationally ambiguous, with multiple viable model choices These findings highlight a core Agent Ops challenge: model selection and routing inside agents is a runtime decision, not a one-time architecture choice. As agents increasingly combine LLM reasoning with structured prediction, understanding the operational strengths and failure modes of tabular models becomes essential for building robust, cost-aware agent systems.

Reusable Evaluators and Template Library: LangSmith Eval Updates

LangSmith introduces reusable evaluators and a library of 30+ evaluator templates to standardize and scale agent evaluation across projects. Teams can define evaluation logic once and apply it across tracing workflows, ensuring consistent safety checks, response quality metrics, and trajectory validation. The templates cover safety (prompt injection, PII, toxicity), response quality, multi-step agent trajectories, user behavior analysis, and multimodal outputs. These evaluators support both online monitoring of production traffic and offline experimentation, enabling teams to detect failures, analyze agent decisions, and continuously improve performance without rebuilding evaluation logic from scratch.

Better-Harness: Using Evals to Iteratively Improve Agent Harnesses

Use evaluation-driven feedback loops to iteratively improve agent harnesses and achieve better generalization in production. Better-Harness treats evals as training data for agents, where each test case provides a learning signal to optimize prompts, tools, and workflows. The system combines curated eval sourcing (hand-written cases, production traces, external datasets), structured tagging for behavioral coverage, and holdout sets to prevent overfitting. It introduces a compound system approach—data sourcing, experiment design, optimization, and human review—to continuously refine agent performance. Key practices include mining production traces for failures, using tagged eval subsets for cost-efficient testing, and pairing automated improvements with human validation to avoid reward hacking and ensure real-world reliability.

Continual Learning in AI Agents Happens Across Model, Harness, and Context Layers

Learn how AI agents improve over time by optimizing three distinct layers: model weights, harness infrastructure, and external context/memory. The piece breaks down techniques like SFT and RL for model updates, harness optimization via trace analysis and systems like Meta-Harness, and dynamic context learning through persistent memory, tenant-level configuration, and runtime updates. It highlights practical strategies such as offline evaluation loops, agent trace logging, and 'dreaming' workflows to iteratively refine agent performance without retraining models, emphasizing scalable alternatives to weight updates.