Prefactor
Stop risky AI agent actions before they reach production users.
Quick answer
Prefactor — Stop risky AI agent actions before they reach production users. It's freemium. Best for engineering teams deploying production AI agents that handle sensitive user data or financial operations.
Prefactor is a real-time AI agent evaluation and enforcement layer that monitors, scores, and blocks risky agent behavior directly in production environments. Built for engineering teams shipping AI agents to real customers, Prefactor sits between your agent logic and the outside world, intercepting every run and scoring it for quality, drift, and risk before any action executes. Unlike observability-only platforms that surface problems after the fact, Prefactor can actively pause or block high-risk operations such as PII exposure or unauthorized financial actions, giving teams genuine runtime enforcement rather than a dashboard full of alerts nobody acted on. Native SDKs for TypeScript and Python make it straightforward to instrument agents built on popular frameworks including LangChain, Claude, Vercel AI, OpenClaw, and LiveKit, so integration fits into existing workflows without a major rewrite. Every agent run receives both LLM-as-judge evaluations and technical qualitative assessments, and teams can configure human-in-the-loop approval flows for sensitive action categories. Prefactor competes most directly with LangSmith and Arize Phoenix but differentiates itself by focusing on enforcement and blocking rather than pure logging and tracing.
Key features
- Real-time agent run scoring for quality, drift, and risk using LLM-as-judge and technical evaluations
- Runtime enforcement that can pause or block high-risk actions like PII exposure or financial transactions before execution
- Native TypeScript and Python SDKs with support for LangChain, Claude, Vercel AI, OpenClaw, and LiveKit
- Human-in-the-loop approval workflows for sensitive agent actions alongside automatic blocking for the highest-risk scenarios
Pros & cons
- +Blocks risky agent actions in real time rather than simply logging them after the fact
- +Generous free tier of 25,000 spans per month with no credit card required
- +Broad framework compatibility through native SDKs covers most major agent development stacks
- −Paid tier pricing is not publicly listed, making budget planning difficult without contacting sales
- −SOC 2 Type II certification is still in progress, which may be a blocker for some enterprise procurement teams
Pricing
25,000 spans/month, no credit card required
Contact for pricing
Contact for pricing
Who is it for
- →Engineering teams deploying production AI agents that handle sensitive user data or financial operations
- →Companies that need compliance-grade oversight of autonomous agent behavior without halting development velocity
- →Developers building on popular agent frameworks who want enforcement guardrails without rebuilding their agent architecture
Frequently asked questions
Is Prefactor free?
Yes, Prefactor offers a free tier that includes 25,000 spans per month with no credit card required, making it accessible for teams evaluating the platform or running smaller agent workloads.
What is Prefactor best used for?
Prefactor is best used by engineering teams shipping AI agents to real customers who need runtime enforcement, not just observability. It is particularly valuable when agents handle sensitive data, financial transactions, or other high-risk actions that must be intercepted before execution.
What are the best alternatives to Prefactor?
The closest alternatives are LangSmith from LangChain and Arize Phoenix. Both offer agent tracing and evaluation capabilities, but they focus primarily on observability and logging rather than active runtime blocking, which is Prefactor's core differentiator.
Is Prefactor safe to use?
Prefactor is designed specifically to improve the safety of AI agent deployments by scoring runs for risk and blocking dangerous actions before they execute. The company is actively pursuing SOC 2 Type II certification, which is currently in progress.
How much does Prefactor cost?
The free tier covers 25,000 spans per month at no cost and requires no credit card. Paid plans for higher usage are available but pricing is not publicly listed, so teams needing more capacity should contact Prefactor directly for a quote.
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