LangSmith Updates Tracing View for Jev-Style Decision Models
On September 23, LangChain founder Harrison Chase announced that LangSmith updated its tracing view to better visualize Jev-style "decision model" calls, and LangChain's official account confirmed support for decision models including Jev and SemIf.
Confirmed
- LangSmith's updated tracing view shows state, question, options, and output for each Jev-style call.
- LangSmith also supports SemIf and other decision models, giving developers visibility into each decision step for faster debugging.
- Chase's core view: future agents will be complex systems composed of many LLM calls, many of them Jev-style decision models with minimal output.
Why it matters
- Decision models output very concise results that are hard to interpret in legacy tracing UIs; native visualization helps developers debug and iterate on agents with more confidence.
- The update reflects an architectural shift from single large calls to systems orchestrated by many fine-grained decision calls, and observability tooling must evolve accordingly.
2026-09-23 ~ 2026-09-23 · 5 related posts
Primary sources
- [source] LangSmith adds dedicated tracing UI for Jev-style decision model calls in agents — hwchase17 · 2026-09-23
- LangSmith ships improved tracing UI for Jev-style decision models — BraceSproul · 2026-09-23
- [source] LangSmith Adds Support for Decision Models Jev and SemIf for Step-Level Debugging — LangChain · 2026-09-23