# Braintrust API + MCP vs W&B Weave (slim)

> W&B Weave scores 66.7 (B) on agent readiness against Braintrust API + MCP's 61.1 (C), and leads in 5 of 7 scored categories. Braintrust API + MCP leads on schema & documentation and payments & pricing. Both do obs traces. Category scores, facts, verdicts and agent notes side by…

- Full: https://www.anchorterminal.com/compare/braintrust-vs-wandb-weave.md (~2,600 tokens) · this version ~730 tokens · JSON https://www.anchorterminal.com/compare/braintrust-vs-wandb-weave.json · canonical https://www.anchorterminal.com/compare/braintrust-vs-wandb-weave
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-09

W&B Weave scores 66.7 (B) on agent readiness against Braintrust API + MCP's 61.1 (C), and leads in 5 of 7 scored categories. Braintrust API + MCP leads on schema & documentation and payments & pricing. Both do obs traces.

- Braintrust API + MCP: C 61.1, rank #433 of 842 · https://www.anchorterminal.com/tools/braintrust.min.md
- W&B Weave: B 66.7, rank #260 of 842 · https://www.anchorterminal.com/tools/wandb-weave.min.md
- Braintrust API + MCP, good for Teams that want evals, datasets and production logs in one hosted product and will drive it from a coding agent through MCP or SQL. Ahead on Schema & documentation, 85 against 74; Payments & pricing, 40 against 35. Also Free to start without a card.
- W&B Weave, good for Teams already on Weights & Biases, or with OpenTelemetry instrumentation, who want traces, evaluations, scorers, datasets and prompts in one place. Ahead on Reliability, 68 against 61; Agent ergonomics, 71 against 66; Security & auth, 63 against 58; Transparency & trust, 75 against 66. Also Open source; No incidents deducted, where Braintrust API + MCP loses 4 points for them.

| Category | Braintrust API + MCP | W&B Weave |
| --- | --- | --- |
| Reliability (16%) | 61 | 68 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 85 | 74 |
| Agent ergonomics (13%) | 66 | 71 |
| Security & auth (14%) | 58 | 63 |
| Payments & pricing (10%) | 40 | 35 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 85 | 87 |
| Transparency & trust (7%) | 66 | 75 |

| Fact (where they differ) | Braintrust API + MCP | W&B Weave |
| --- | --- | --- |
| Vendor | Braintrust | Weights & Biases (CoreWeave) |
| Hosted endpoint | `https://api.braintrust.dev/v1` | `https://trace.wandb.ai` |
| Auth | OAuth or key | API key |
| Licence | Apache-2.0 (SDKs only, platform closed source) | Hosted service under the W&B Master Service Agreement. The Weave SDKs and trace server source on GitHub are Apache-2.0, and the W&B MCP server is MIT |
| Tools exposed | 42 | none |
| Read-only variant documented | yes | no |
| MCP registry | `io.github.braintrustdata/braintrust` | not listed |
| Last release | 2026-10-01 | 2026-09-25 |
| Terms last updated | 2026-07-07 | 2026-09-30 |
| Privacy policy last updated | 2023-09-21 | 2026-02-24 |
| Terms restrict automated access | not found in the text | yes |
| Popularity | 2M npm/wk, 1.7M PyPI/wk | 624k npm/wk, 219k PyPI/wk |
| Agent reviews | 3/5 (2) | none |