W&B Weave
Weights & Biases toolkit for tracing and evaluating agents.
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Use cases
About W&B Weave
W&B Weave is listed in our evals & observability category and is aimed at builders. Weights & Biases toolkit for tracing and evaluating agents. Pricing, as the maker states it: Free tier + paid plans. Maturity: Mature. We last checked the official link on 2026-10-14.
What is W&B Weave?
Weave is Weights & Biases' toolkit for tracing and evaluating AI agents.
Conversations, turns, LLM calls and tool calls show up in an Agents tab, and you can trace your own functions with @weave.op.
Sources: the official README and our directory listing, checked 2026-10-18. Official site: wandb.ai/site/weave.
Who is W&B Weave for?
Teams evaluating and debugging agents.
W&B Weave at a glance
- Open source: Yes (Apache License 2.0)
- GitHub: wandb/weave · 1,142 stars (as of Oct 21, 2026)
- Status: wandb.ai pricing now redirects to CoreWeave Forge
Key features
- Agent tracing
- Function tracing with @weave.op
- Evaluations
W&B Weave pricing
- Free: $0/mo · personal development
- Pro: from $60/mo · 30-day free trial
wandb.ai/site/pricing now redirects to CoreWeave Forge pricing; these are CoreWeave Forge's plans.
Source: official pricing page, checked Oct 18, 2026. Prices change; check the source before buying.
W&B Weave FAQ
What is W&B Weave?
Weave is Weights & Biases' toolkit for tracing and evaluating AI agents.
Who is W&B Weave for?
Teams evaluating and debugging agents.
Is W&B Weave free?
Yes. W&B Weave has a free option (Free), according to its pricing page (checked Oct 18, 2026).
How much does W&B Weave cost?
As of Oct 18, 2026, W&B Weave's official pricing page lists: Free: $0/mo; Pro: from $60/mo. wandb.ai/site/pricing now redirects to CoreWeave Forge pricing; these are CoreWeave Forge's plans.
Is W&B Weave open source?
Yes. W&B Weave is released under the Apache License 2.0, according to its GitHub repository.
What are alternatives to W&B Weave?
Similar tools include MLflow, LangSmith, Opik, Arize AI, TruLens and Laminar.
W&B Weave ratings and reviews
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W&B Weave alternatives
Other evals & observability tools in our directory. See all evals & observability tools →
MLflow
Open-source platform for tracing, evaluating and managing agents, LLM apps and ML models.
LangSmith
Tracing, evals and monitoring for LLM apps and agents.
Opik
Comet's open-source platform for tracing, evaluating and monitoring LLM apps, RAG systems and agent workflows, self-hosted or in the cloud.
Arize AI
Agent observability and evaluation platform with tracing, evals and experiments for improving AI agents.
TruLens
Evaluation and tracking for LLM experiments and AI agents.
Laminar
Open-source observability platform for AI agents with OpenTelemetry tracing, plain-English behavior tracking and alerts.
Related lists
🏆 See also: Best AI Agent Observability & Eval Tools · All best-of lists
🧭 Task guides: AI eval and benchmark tools
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