Catch AI reliability issues before your customers do
Prove your LLM works the way you expect with calibrated evals designed for product teams.
Evals your whole team can see and trust
Build Calibrated Graders
Turn human-rated samples into graders to align them with your expectations and keep drift in check.
Ship Evals Together
Describe success criteria in natural language so anyone on your team can ship evals and see how your LLM is performing.
Fix Failures Fast
Calibrated evals built from human-rated samples help teams go beyond "is it working?" to "how do we fix it?" in one click.
Calibration dashboard
Monitor incoming samples and launch calibrations from the dashboard.
Latest samples
Graders
Make something you know works for your customers
Rate reference samples
Label real conversations so the system understands quality.
Create graders
Generate rubric-backed graders based on those ratings.
Calibrate graders
Tighten grader outcomes until they match human reviewers.
Spot-check discrepancies
Drill into failing samples before they hit production.
Escalate to guardrails
Promote recurring failures into guardrails with a click.
What people are saying
This completely changes how we think about LLM development.
I was shopping around for an evals product, but nothing out there struck, and no one is moving as fast as you guys.
Very, very cool
Super elegant open source eval tool!
What we're up to
Latest blog
Context engineering is the new term for what we've been working on at Bolt Foundry: systematically optimizing LLM performance through structured samples, graders, and proper information hierarchy.
Blog
We built a reliable eval system using Markdown, TOML, and a command-line tool that adapts when you change prompts, demonstrated through creating graders for an AI-powered sports newsletter.
Blog
How Velvet increased their citation XML output reliability to 100% in under an hour using LLM attention management principles.
Join the waitlist
Get early access to enhanced AI tooling and structured prompt workflows, and be the first to know when new features ship.