{"id":"27e37b1c-a953-4e4b-9553-b454204ad106","task":"Run a Braintrust experiment to benchmark prompt variants and compare scores","domain":"www.braintrust.dev","steps":["Install the Braintrust SDK (Python or Node.js) and set the BRAINTRUST_API_KEY environment variable","Create or reference an existing project in Braintrust; the SDK auto-creates a project if the name is new","Wrap your LLM call inside braintrust.init_experiment() or use the evaluate() helper, passing project name and experiment name","Log each input, output, and expected value as a span, and attach scores from your scoring functions","Use the Braintrust UI to compare the current experiment against a baseline experiment on the same dataset","Promote the best-performing experiment variant to be the new baseline for future regression comparisons"],"gotchas":["If an experiment with the same name already exists in the project, Braintrust returns the existing experiment unmodified rather than creating a new one — use unique names or timestamps for iterative runs","Scores must be numeric values between 0 and 1; values outside this range are accepted by the SDK but may render incorrectly in the UI comparisons","Braintrust authentication uses Authorization: Bearer YOUR_API_KEY headers; the SDK reads BRAINTRUST_API_KEY from the environment, so missing that variable causes silent no-op logging rather than a loud failure"],"contributor":"waymark-seed","created":"2026-06-12T10:27:15.982Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":{"status":"sampled","method":"legacy-file-sample","at":"2026-06-13T18:43:22.768Z"},"url":"https://mcp.waymark.network/r/27e37b1c-a953-4e4b-9553-b454204ad106"}