Arinti.Langfuse.Tracing.SemanticConventions 1.0.0-alpha.1

Arinti.Langfuse.Tracing.SemanticConventions

Strongly typed C# constants for three related attribute namespaces:

• GenAIAttributes — OpenTelemetry semantic conventions for Generative AI spans (SemConv 1.41 GenAI), e.g. gen_ai.operation.name, gen_ai.request.model, gen_ai.usage.input_tokens.
• LangfuseAttributes — Langfuse-specific attributes (langfuse.trace.*, langfuse.observation.*) that override or supplement the OTel spec when a span is destined for Langfuse OTLP ingestion.
• OtelAttributes — the small cross-cutting OTel namespaces (user.*, session.*, deployment.*) that Langfuse recognises as fallbacks for its langfuse.* keys when you prefer portable instrumentation over the Langfuse-prefixed form.

No runtime dependencies. Drop the package into any project that writes to Activity / ActivitySource and you stop typing magic keys. Attribute values ("chat", "openai", "generation", …) stay as string literals — the package ships attribute names only, since that's all the upstream SemConv registries declare. See SemConv 1.41 GenAI for the allowed values per attribute.

Usage

using Arinti.Langfuse.Tracing.SemanticConventions;

using Activity? chat = source.StartActivity($"chat {model}");
chat?.SetTag(GenAIAttributes.Operation.Name, "chat");
chat?.SetTag(GenAIAttributes.Provider.Name, "openai");
chat?.SetTag(GenAIAttributes.Request.Model, model);
chat?.SetTag(GenAIAttributes.Request.Temperature, 0.2);
chat?.SetTag(GenAIAttributes.Response.TimeToFirstChunk, ttftSeconds);
chat?.SetTag(GenAIAttributes.Usage.InputTokens, usage.InputTokens);
chat?.SetTag(GenAIAttributes.Usage.OutputTokens, usage.OutputTokens);

// Langfuse-specific identity overrides
chat?.SetTag(LangfuseAttributes.Trace.SessionId, sessionId);
chat?.SetTag(LangfuseAttributes.Trace.UserId, userId);
chat?.SetTag(LangfuseAttributes.Observation.Type, "generation");

When you have both gen_ai.* and langfuse.observation.* set

Langfuse honours langfuse.observation.* with higher precedence — see the Property Mapping section of the Langfuse OpenTelemetry docs for the full priority order.

Several observation-level attributes (ModelName, ModelParameters, UsageDetails, Input, Output) are redundant if you already emit their gen_ai.* equivalents — Langfuse resolves the same field from the fallback chain. The constants exist for consumers that prefer the Langfuse-prefixed shape; each carries a <seealso/> pointing at the spec-portable alternative.

Generated, not hand-written

GenAIAttributes.cs, OtelAttributes.cs, and LangfuseAttributes.cs are produced by the OpenTelemetry Weaver tool from the upstream SemConv registry (pinned in weaver/registry/manifest.yaml) and a local langfuse.* registry under weaver/model/langfuse/. Do not edit those files by hand — they carry an <auto-generated> marker and any manual change is overwritten the next time anyone re-runs generation.

To refresh against a newer SemConv release or after editing the Langfuse registry, clone this repo and run:

weaver/generate.sh