Comet has placed Opik, its open source platform for tracing and scoring LLM agents, in the Nebius AI Cloud Applications catalog, so teams that rent compute from Nebius can add agent observability without bringing in a separate vendor stack.
The pitch is proximity: debugging and evaluation tools sitting in the same cloud as the GPUs that train and serve the models. Comet calls the listing the first step in a wider collaboration between Opik and Nebius, though it gives no timeline and does not say what later phases will add.
Opik records LLM calls and agent traces, keeping each run's inputs, outputs and intermediate reasoning so an engineer can reconstruct why an agent chose a particular path. Teams can line up runs from different model versions side by side and catch regressions before a change ships, whether the workload is one model or a multi-agent system with many moving parts. On the evaluation side, the tool supports custom metrics, automated scoring at scale and benchmarking across experiments. Per Comet, Nebius customers can now run those evaluations next to their training and inference jobs instead of exporting data elsewhere.
Comet also insists this is more than a marketplace entry. The company says Comet and Opik were tested and tuned on Nebius infrastructure, with engineers from both firms working on the fit. That is Comet's own characterization; the announcement offers no performance numbers or benchmarks to show what the tuning changed.
The deal reaches past Opik. Comet is opening its older MLOps tools to Nebius customers as well: Experiment Management for logging training runs, hyperparameters and metrics; a Model Registry that versions and promotes models with lineage back to the experiments behind them; and Production Monitoring for models already deployed. Comet's argument is that a team fine-tuning on Nebius GPU clusters could keep the whole lifecycle, from the first training run to a monitored production agent, on one stack. Because Opik is open source, the company expects teams to start with the free tooling and graduate to its managed platform later. What that managed tier costs when bought through Nebius is not stated anywhere in the announcement.
