Technology · Agentic → Observability · Open Core · wiki:deep
W&B Weave
Weave is Weights & Biases’ toolkit for developing generative AI apps: log/debug LM inputs/outputs/traces, run rigorous evaluations, and organize experiment→eval→production artifacts inside the W&B ecosystem. Install via pip install weave, weave.init(...), and @weave.op tracing. Apache-2.0 library with W&B account/cloud gravity (free tier available). Repo notes older “engine/boards” code; current focus is tracing + evaluations.
Why it matters here
Prefer Weave when experiments already live in W&B. Prefer Langfuse/Phoenix/Opik for dedicated self-host LLM-ops UIs; OpenLLMetry for OTEL export; Helicone for gateway logging.
How it works
Initialize Weave against a W&B project; decorate functions with @weave.op to build trace trees; use Weave evals to compare runs.
pip install weave; create/login W&B.weave.init("project").- Trace ops / LLM calls.
- Run evaluations and iterate in W&B/Weave UI.
Related: arize-phoenix · comet-optik · helicone · topics/09-self-monitoring
Scroll inside the canvas to pan
When to reach for it
- Use when: W&B is already the experiment system of record.
- Skip when: you need self-host OSS LLM platform without W&B (langfuse, phoenix, comet-optik) or OTEL-only (openllmetry).
- Prefer instead: Langfuse as cell default if no W&B lock-in.
Limits
- Account/cloud dependency for full workflow.
- Not company operational ledger.
- Historical codebase noise: ignore paused engine/boards paths.
- Decorator discipline: untraced paths stay invisible.
Linked from
Catalog backlinks — what points here (wiki “what links here”).
Features
- cost-latency-ops
- observability-auditability
- r2-09-self-monitoring
- r2-14-process-mining
- r2-34-decision-lineage
- r2-38-abm-span-mapping
- r2-47-trace-maturity-gate
- wt-runtime
Stacks
Peers
What we checked
Claims below are backed by science sources on disk.
Toolkit / tracing role
wandb/weave · MODERATE
“Based on OpenTelemetry to increase compatibility and reduce vendor lock-in”
Docs
Weave documentation · MODERATE
“Observability is essential for understanding and debugging LLM applications. Unlike traditional software, LLM applications involve complex, non-deterministic interactions that can be challenging to monitor and debug.”
Contrast vs Langfuse
Langfuse contrast · MODERATE
“Langfuse is an open-source LLM engineering platform that helps teams collaboratively debug, analyze, and iterate on their LLM applications.”
In this research stack
Features and peers linked from the catalog map — not a second product surface.
Features it supports
- cost-latency-ops
- observability-auditability
- r2-09-self-monitoring
- r2-14-process-mining
- r2-34-decision-lineage
- r2-38-abm-span-mapping
- r2-47-trace-maturity-gate
- wt-runtime
Same cell
Stack
Document management
No DM vendor crosswalk edges yet.
Source
Primary repo github.com/wandb/weave · Open Core
technologies/wandb-weave/README.md
Research inventory
9 tags · 14 out · 15 in · 3 artifacts · 1 gaps · 29 corpus docs
Catalog tags
- landscape.layer
- Agentic
- landscape.subcategory
- Observability
- license_tag
- Open Core
- maps.dm
- absent
- maps.features
- 8
- one_liner
- Agentic
- review.depth
- science
- slug
- wandb-weave
- title
- W&B Weave
Artifacts
- dm_map · absent
- features_map · present · technologies/wandb-weave/features.md
- readme · present · technologies/wandb-weave/README.md
Out · alternative_to
- arize-phoenixtechnology
- comet-optiktechnology
- heliconetechnology
- langfusetechnology
- langsmithtechnology
- openllmetrytechnology
Out · maps_to
- cost-latency-opsfeature
- observability-auditabilityfeature
- r2-09-self-monitoringfeature
- r2-14-process-miningfeature
- r2-34-decision-lineagefeature
- r2-38-abm-span-mappingfeature
- r2-47-trace-maturity-gatefeature
- wt-runtimefeature
In · alternative_to
- arize-phoenixtechnology
- comet-optiktechnology
- heliconetechnology
- langfusetechnology
- langsmithtechnology
- openllmetrytechnology
In · in_stack
- agentic-observabilitystack · alternative_slot
In · maps_to
- cost-latency-opsfeature
- observability-auditabilityfeature
- r2-09-self-monitoringfeature
- r2-14-process-miningfeature
- r2-34-decision-lineagefeature
- r2-38-abm-span-mappingfeature
- r2-47-trace-maturity-gatefeature
- wt-runtimefeature
Corpus tags
- category
- Agentic → Observability
- dedication
- open-core
- feature
- cost-latency-opsobservability-auditabilityr2-09-self-monitoringr2-14-process-miningr2-34-decision-lineager2-38-abm-span-mappingr2-47-trace-maturity-gatewt-runtime
- kind
- map_edgetech_featurestech_quotetech_readmetech_science_sourcetech_section
- needs_deepen
- false
- quality
- ok
- section
- EvidenceFeatures mapGitHub mapHow it worksLimits & failure modesLinksScientific notesWhat it isWhen to use / skipWhy it matters here
- slug
- wandb-weave
- source_id
- langfuse-contrastweave-docsweave-github
- technology
- wandb-weave
Corpus documents (29)
map_edge · 8
- wandb-weave → cost-latency-ops
- wandb-weave → observability-auditability
- wandb-weave → r2-09-self-monitoring
- wandb-weave → r2-14-process-mining
- wandb-weave → r2-34-decision-lineage
- wandb-weave → r2-38-abm-span-mapping
- wandb-weave → r2-47-trace-maturity-gate
- wandb-weave → wt-runtime
tech_features · 1
- W&B Weave · features
tech_quote · 6
- W&B Weave · langfuse-contrast
- W&B Weave · langfuse-contrast
- W&B Weave · weave-docs
- W&B Weave · weave-docs
- W&B Weave · weave-github
- W&B Weave · weave-github
tech_readme · 1
- W&B Weave
tech_science_source · 3
- W&B Weave · langfuse-contrast
- W&B Weave · weave-docs
- W&B Weave · weave-github
tech_section · 10
- W&B Weave · Evidence
- W&B Weave · Features map
- W&B Weave · GitHub map
- W&B Weave · How it works
- W&B Weave · Limits & failure modes
- W&B Weave · Links
- W&B Weave · Scientific notes
- W&B Weave · What it is
- … +2 more