LangChain Launches LangSmith Fine-Tuning Beta with smithtune CLI
On September 25, LangChain launched LangSmith Fine-Tuning and the open-source smithtune CLI in public beta at Interrupt 26. It converts agent traces recorded in LangSmith into SFT datasets for training dedicated open-weight small models, with hosted inference from Fireworks AI and Baseten, forming an end-to-end pipeline from data to fine-tuning to deployment, aiming to cut inference cost and latency.
Confirmed
- LangSmith Fine-Tuning and smithtune CLI are in public beta, released by LangChain with Baseten and Fireworks AI as partners, announced at Interrupt 26
- Workflow: identify and export traces from LangSmith, convert them into training data for SFT, train and deploy with a single command, then run evaluations on Fireworks
- LangSmith processes hundreds of millions of agent traces daily, which can be turned into high-quality fine-tuning data
- Official goal is training dedicated small models on production traces to reduce cost and latency
Why it matters
- It closes the loop from observability data to fine-tuning to deployment: traces previously used mainly for debugging and evaluation now become fine-tuning assets
- With hosted inference from Fireworks and Baseten, the LangChain ecosystem extends from frameworks and observability into model customization, lowering the barrier for developers to fine-tune their own models
2026-09-25 ~ 2026-09-25 · 11 related posts
Primary sources
- LangChain launches LangSmith Fine-Tuning with smithtune CLI to train models from agent traces — LangChain ·
- LangChain launches LangSmith Fine-Tuning and smithtune CLI to turn traces into tuned models — LangChain ·
- LangSmith Launches Fine-Tuning: Train Models on Your Agent Traces via Baseten — baseten ·
- LangSmith Fine-Tuning launches with Fireworks AI and Baseten for open-weight models — hwchase17 · 2026-09-25
- [source] LangChain launches LangSmith Fine-Tuning with smithtune CLI to train models from agent traces — LangChain · 2026-09-25
- [source] LangChain launches LangSmith Fine-Tuning and smithtune CLI to turn traces into tuned models — LangChain · 2026-09-25
- LangSmith Launches Fine-Tuning With smithtune CLI, Trained on Your Agent Traces — baseten · 2026-09-25
- LangChain Launches LangSmith Fine-Tuning and smithtune CLI in Public Beta — LangChain · 2026-09-25
- LangChain launches SmithTune: fine-tune custom models from LangSmith traces — LangChain · 2026-09-25
5 near-duplicate retellings: LangChain · LangChain · LangChain · LangChain · baseten