DSPy 3.4.0 ships native Jev/System One support and ReAnchor optimizer
DSPy 3.4.0 was released on Sept 25 with two headline features: native support for Jev and other System One models, and a new optimizer called ReAnchor. The news was first announced by dbreunig (Drew Breunig) and spread the next day via reposts from viksit, dairai, CShorten30, hardimanjames and others.
Confirmed
- DSPy 3.4.0 natively supports Jev and System One models, usable directly with existing DSPy signatures.
- ReAnchor, released by Drew Breunig and Isaac Miller, is an optimizer built for TypeSafe's Jev and other System One models, designed to calibrate model outputs by confidence.
- According to dbreunig, Jev is not an LLM and does not output text; the integration automatically calibrates Jev's output thresholds against the user's evaluation metrics, works with existing signatures and metrics, and switching between an LM and Jev takes a one-line change.
- dbreunig added that because the ReAnchor-Jev connection is signature-compatible, it can run directly on existing LM programs, and delivered several improvements in his tests.
Unconfirmed
- A repost by CShorten30 claims the release also substantially improves LLM capabilities via the sister library LM15; this has not been confirmed by the original publisher.
Why it matters
Decision models like Jev that do not output text were previously hard to incorporate into DSPy's programmatic orchestration. Native support means developers can mix traditional LMs with Jev in the same framework, with ReAnchor handling confidence calibration automatically, lowering integration and tuning costs.
2026-09-25 ~ 2026-09-26 · 10 related posts
Primary sources
- DSPy 3.4.0 ships native Jev support and ReAnchor optimizer for confidence calibration — dbreunig ·
- New DSPy support for Jev: optimizer auto-calibrates output thresholds, one-line model switching — dbreunig ·
- DSPy introduces ReAnchor, an optimizer that runs programs on TypeSafe's System One decision model Jev — dbreunig ·
- [source] DSPy 3.4.0 ships native Jev support and ReAnchor optimizer for confidence calibration — dbreunig · 2026-09-25
- [source] DSPy introduces ReAnchor, an optimizer that runs programs on TypeSafe's System One decision model Jev — dbreunig · 2026-09-25
- [source] New DSPy support for Jev: optimizer auto-calibrates output thresholds, one-line model switching — dbreunig · 2026-09-26
- DSPy 3.4.0 adds native System One model support and ReAnchor optimizer — hardimanjames · 2026-09-26
- DSPy launches ReAnchor optimizer for System One models like Jev — dbreunig · 2026-09-26
- DSPy 3.4.0 adds native System One model support with new ReAnchor optimizer — dair_ai · 2026-09-26
4 near-duplicate retellings: dbreunig · viksit · CShorten30 · lateinteraction