
Cart Assistant: Agentic Grocery Shopping on Uber Eats
6/16/2026
This post details the technical architecture and implementation of Uber Eats' Cart Assistant, an AI-powered system for agentic grocery shopping. It describes the shift from a search-first to a cart-first shopping paradigm, enabled by a multi-prompt state graph. Key technical contributions include: the Cart Plan Generation stage using LLMs for structured output of planned items with search terms, context, and constraints; Candidate Retrieval and Enrichment via backend search and catalog APIs; Semantic Relevance Judging using LLM rubrics; Price and Deal Constraint Enforcement through deterministic optimization; Quantity Selection combining LLM reasoning with deterministic arithmetic; Guardrails (deterministic and LLM-based) for safety and boundedness; and optimizations for parallelism and latency. The post also highlights the importance of an evaluation-driven development framework for measuring and improving LLM-based systems.