Tooling

Evaluation and observability integrations that plug into Fabric evals, events, and telemetry.

Fabric owns the eval and telemetry contracts (@fabric-harness/evals, SubmissionTelemetrySink, OTel span exporters) while applications own vendor accounts and credentials. The integrations below build on those seams, so vendor SDKs remain optional dependencies of your workspace.

Integration	What it adds	Guide
Braintrust	Eval logging and experiment comparison for `fh test` suites.	Recipe + env wiring.
Jetty	Grades job output with a separately deployed rubric and stores comparable trajectories.	Deployment + rubric setup.
OpenTelemetry	Span export for prompts, tools, and submissions to any OTLP collector.	Exporter configuration.
Sentry	Error capture for server routes and agent turns.	DSN + event hook wiring.
Vitest evals	Runs eval suites inside your existing Vitest setup.	Suite conventions.

Telemetry integrations observe execution — they never gate it. A sink or exporter failure is reported and swallowed; agent turns and submissions settle regardless.