OpenRouter Launches Span-01 & Span-01 Lite: Agent Trace Decision Models

Key Info

OpenRouter makes available Span-01 and Span-01 Lite from RespanAI, decision models that analyze agent traces and return probabilities for specific behaviors like user frustration or tool call safety. Pricing: Span-01 at $0.02 per 1M input tokens with free output; Lite is free.

Highlights

• Span-01 claims #1 on the Behavior Benchmark, with an RLAIF-based hyper-parallel reasoning design.
• Compared to existing options: 2x cheaper and 18% better than Jev; 700x cheaper and 4% better than GPT-6 Luna.
• Intended use cases include gating risky tool calls, flagging support conversations needing humans, and labeling eval traces in bulk.
• Supports plain text or full spans of system/user/assistant/tool messages with no cap on span size.