StartupY Combinator (W25)
Lucidic
Custom models and harnesses trained on your data; launched to debug and evaluate agents in production.
Lucidic launched on Hacker News in July 2025 to debug, test and evaluate AI agents in production (116 points). Its site now reads "Custom Models & Harnesses Trained on Your Data", a move from observing agents to training the models and harnesses behind them. Y Combinator W25.
Neighbours in the directory
San Francisco, CA · Est. 2022
The de-facto standard toolkit for building LLM applications and agents.
LangChain makes the LangChain framework and LangGraph, the low-level orchestration standard for stateful, controllable agents, plus the LangSmith platform for tracing, evaluating and monitoring them in production.
~$75M raised
San Francisco, CA · Est. 2023
Enterprise-grade evals, data and AI gateway.
Braintrust turns prompts and agent traces into testable datasets and CI, plus an inference gateway — helping teams measure whether harness changes actually improve agent quality.
Berkeley, CA · Est. 2020
Observability and evaluation for AI — makers of OSS Phoenix.
Arize traces and evaluates LLM and agent systems in production; their open-source Phoenix tracer is a common instrumentation choice for agent harnesses that need to be debuggable.
Sources
Verified Oct 29, 2026