Introduction
Connect Eve tracing, Langfuse prompt management, subagents, and skills.
@vantezzen/langfuse-eve turns Langfuse into the prompt and tracing layer for your Eve
agents. Use Eve-native define functions to load instructions and skills from Langfuse,
compile them with Eve context, and automatically attach the exact prompt version to every
generation, including calls made by subagents. Complete Eve traces, session lineage, and
Vercel AI Gateway data flow back to Langfuse without maintaining span processors, prompt
adapters, or context-propagation glue in your application.
One integration instead of glue code
The official Langfuse setup gets Eve's OpenTelemetry spans into Langfuse. Building the rest of the connection yourself means wiring the span processor and filters, fetching and compiling prompts, translating Eve context into prompt variables, tracking prompt versions, and carrying that information through subagent sessions.
| Capability | Basic Langfuse integration | @vantezzen/langfuse-eve |
|---|---|---|
| Export Eve spans to Langfuse | ✅ | ✅ |
| Configure and filter span processors | ❌ Copy and maintain setup code | ✅ One Eve provider definition |
| Load and compile agent prompts | ❌ Custom prompt loader | ✅ defineLangfuseInstructions() |
| Use Eve context as prompt variables | ❌ Custom adapter | ✅ Typed variables resolver |
| Link generations to prompt versions | ❌ Manual attributes | ✅ Automatic prompt attribution |
| Attribute prompts across subagents | ❌ Manual context propagation | ✅ Automatic for each agent |
| Create Langfuse-backed Eve skills | ❌ Custom dynamic skills | ✅ defineLangfuseSkill() |
| Load a prompt folder as skills | ❌ Custom listing and caching | ✅ defineLangfuseSkills() |
| Group child traces and retain lineage | ❌ Manual identifiers | ✅ Automatic root-session grouping |
| Record AI Gateway IDs and costs | ❌ Custom metadata mapping | ✅ Normalized, filterable metadata |
The library still uses Eve's OpenTelemetry pipeline and the official Langfuse span processor. It packages the integration layer around them rather than introducing another tracing backend or prompt format.
Continue
Quick start
Install the package, enable complete traces, and connect the main agent prompt.
Trace integration
See what is recorded, configure privacy, and add trace metadata.
Agent prompts
Configure root prompts, subagent prompts, variables, and fallbacks.
Skills from Langfuse
Expose one prompt or a prompt folder as Eve skills.