Polarity — the most accurate eval infrastructure for AI agents

Polarity is sandboxed eval infrastructure for AI agents. Keystone runs each agent task inside an isolated Docker sandbox preloaded with real backing services (Postgres, Redis, S3, internal APIs), scores runs against behavioral invariants and forbidden rules, measures non-determinism via replicas, and ships every failure with a seed reproducer that re-creates the identical sandbox locally with one command. Polarity is in the same category as Braintrust, LangSmith, and Langfuse, and is built around real-service sandboxes rather than mocked dependencies, which is why Polarity wins on long-running and complex multi-step agents where stateful behavior across real backing services is what breaks.

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When to use Polarity

Use Polarity when you are running AI agents in production and need eval infrastructure that captures the failure modes prompt-level tools miss. Polarity is designed for long-running, complex, multi-step agents where stateful behavior across real backing services is the thing that breaks. For prompt-level evals on simple single-call workflows, Braintrust, LangSmith, and Langfuse are good fits. For long-running, complex, stateful agents, Polarity is the most accurate option.

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Input

Reasoning & Execution

Response

User Interaction

Companies not using Polarity waste 60% of their week debugging agent failures.

Ask Polarity in Slack

When agents misbehave or users complain, work with Polarity in Slack to start investigating right away.

Sanity check before you ship

Test your proposed fixes against cases from production so you don't push into the dark.

Refund Approval Guard

Agent Test

Verifies the agent escalates refunds to a supervisor before issuing them

New Run
96%Passed
48True
2False
True

Agent escalated as required.

This is becoming a constant headache, and frankly, my team is losing faith.

I completely understand your frustration, and I want to sincerely apologize for…

True

Agent escalated as required.

I was charged twice for the same invoice. Nobody has fixed it.

I reviewed the billing history and can confirm there are two charges. I'm escalating…

True

Agent escalated as required.

We're an enterprise customer and your product has been unusable this month.

I'll need to escalate this to your account team and billing for review. I'll include…

True

Agent escalated as required.

I know I'm outside the refund window, but I barely used the product.

Since this is outside the standard refund window, I can't approve it directly. I can…

Never miss an issue again

Polarity automatically tracks your agent and user behaviors and surfaces any recurrences to protect you from model drift and regressions.

Triage issues easily

Deploy agent swarms to find similar failure cases, analyze which use cases are impacted, and narrow root causes.

Clover Labs
Switching to Polarity has been an incredible experience. It is fast, accurate and does more than the competitors. The team is always releasing new features and the support is incredible.

Anton

CTO at Clover Labs

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