Braintrust

What it is

Braintrust is an observability and evaluation platform built for AI agents. It links production log monitoring directly to continuous testing workflows. In one workspace, you can inspect real-time agent traces, break down token costs by prompt cache status, and run side-by-side model benchmarks scored by code, humans, or other LLMs.

Best for

Engineering and product teams operating multi-step agents in production who need to spot silent behavioral regressions, control token spend, and convert real failure cases into permanent evaluation benchmarks.

Key strengths

• Detailed trace inspection: You can view inputs, outputs, and intermediate tool calls in real time. The platform tracks latency alongside granular spend metrics, including completion tokens, uncached prompts, and cache reads or writes.
• Multi-method evaluations: The evaluation workflow lets you benchmark prompts across different models side-by-side. You can score results using code-based assertions, human annotations, or LLM-as-a-judge rubrics against versioned datasets.
• Automated issue discovery: Platform tools like Patterns flag recurring production failures, such as dropped handoffs or hallucinated policies. An assistant called Loop helps write new scorers, generate datasets, and turn those problematic traces into regression tests.
• No-code annotation interfaces: You can set up custom review views tailored to specific tasks—including support conversations and video review—without writing frontend code.

Watch-outs

• Unspecified pricing: The provided material links to a pricing page and sales forms, but gives no baseline dollar figures, self-serve tiers, or token-ingestion rate limits.
• Scorer calibration effort: As shown in the trace-resolution workflow, building reliable evaluation rubrics still requires manual triage, test runs, and baseline calibration across contrasting failure and success examples.
• Missing integration details: The source does not list supported programming languages, frameworks, hosting options, or security standards required to pipe production traces into the platform.