Langfuse v4.39.0
Langfuse v4.39.0 enhances thread tracing, AI gateway observability, and ingestion policy enforcement, while introducing a breaking restructuring of generation metadata namespaces.
Why this signal matters
Langfuse released v4.39.0 with several tracing, gateway, and infrastructure improvements. Key enhancements include thread-level retrieval of conversation history and current turn, Vertex AI support for in-app agent features, and gapless AI gateway traces via phase spans. The release also enforces authorization through policy core for all ingestion events, simulates worker admission in OTEL shadow mode, and adds batching token telemetry. A breaking fix reorganizes generation metadata namespaces in the AI gateway.
Actionable summary
Langfuse v4.39.0 introduces conversation history/current turn retrieval per thread, phase spans and Codex client metadata recording in the AI gateway, and policy-core authorization for ingestion events. Note a potential breaking change in AI gateway generation metadata namespaces.
- Agent usefulness
- 82/100
- Confidence
- 96%
- Canonical data
- JSON + Markdown
What builders should check
- Review downstream applications consuming AI gateway generation metadata, as metadata namespaces were reorganized (PR 17645).
- Verify policy core access rules if running strict ingestion authorization configurations (PR 16715).