Weave

Weave is Weights & Biases' tooling for watching and improving AI systems that are already running. It records traces, organises them by session, turn, step, tool and sub-agent rather than as loose calls, classifies behaviour with built-in and custom signals, sends alerts to chat and webhooks, runs evaluations through an API, and offers a playground for comparing prompts and models against real traces. Guardrails add scorers for safety and quality — toxicity, bias, personal-information detection, hallucination; coherence, fluency, context relevance — and evaluations can be aggregated into leaderboards. It sits inside a larger platform that also covers experiment tracking, model registry and hosting, so it is aimed at teams that already treat model work as a discipline with runs and versions.

It suits a team whose agents are in production and whose new problem is reliability drift — the failure modes that never appeared in offline testing — and it suits organisations that want one vendor for training experiments and for what the deployed system does afterwards. It suits less well a team that wants an open-source observability stack to own end to end, because this is a commercial platform with its own data plane, and it suits less well anyone whose only need is to log calls and look at latency.

Not verified: no traces, evaluations or guardrails were run, so the accuracy of the signals, the scorers and the session model was not observed. The page carried a line asking readers to contact support if they need help retrieving their data; nothing on the pages read explained what it referred to, and no support channel was consulted. The claims on the page — that token cost can be cut sharply, that reported latency stays flat as graph size grows, and the figures in the vendor's own dashboard illustration — are the vendor's own numbers or mock-up data, not measurements taken here. The pricing page was not opened, so tiers and prices are unknown, and the Weave repository was not read, so its licence and release cadence are unchecked.