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Telemetry

Adds OpenTelemetry GenAI attributes to Effect AI spans.

This module models the gen_ai.* attributes used by language model and embedding providers. It includes attribute types, helpers for writing non-null attributes onto existing spans, and a CurrentSpanTransformer service for adding custom span annotations from provider options and response parts.

17 exports Added in v4.0.0 Source

Annotations

addGenAIAnnotations

Added in v4.0.0 Source

Applies GenAI telemetry attributes to an OpenTelemetry span.

When to use

Use when you need to write GenAI request, response, token, or usage attributes onto an existing OpenTelemetry span.

Details

This function adds standardized GenAI attributes to a span following OpenTelemetry semantic conventions.

Gotchas

This function mutates the provided span in-place.

Signature

declare const addGenAIAnnotations: {
  (options: GenAITelemetryAttributeOptions): (span: Span) => void;
  (span: Span, options: GenAITelemetryAttributeOptions): void;
};

addSpanAttributes

Added in v4.0.0 Source

Creates a reusable span-attribute writer for a key prefix and key transformer.

Details

The returned function mutates the supplied span by adding each non-nullish attribute as ${prefix}.${transformedKey}.

Signature

declare function addSpanAttributes(
  keyPrefix: string,
  transformKey: (key: string) => string,
): <Attributes extends Record<string, any>>(span: Span, attributes: Attributes) => void;

Models

AllAttributes type

Added in v4.0.0 Source

All telemetry attributes which are part of the GenAI specification.

Signature

type AllAttributes = BaseAttributes &
  OperationAttributes &
  TokenAttributes &
  UsageAttributes &
  RequestAttributes &
  ResponseAttributes;

BaseAttributes interface

Added in v4.0.0 Source

Telemetry attributes which are part of the GenAI specification and are namespaced by gen_ai.

Signature

interface BaseAttributes {
  readonly system?: (string & {}) | WellKnownSystem | null;
}

GenAITelemetryAttributes type

Added in v4.0.0 Source

The attributes used to describe telemetry in the context of Generative Artificial Intelligence (GenAI) models requests and responses.

Details

These attributes follow the OpenTelemetry generative AI semantic conventions: https://opentelemetry.io/docs/specs/semconv/attributes-registry/gen-ai/

Signature

type GenAITelemetryAttributes = Struct.Simplify<
  AttributesWithPrefix<BaseAttributes, "gen_ai"> &
    AttributesWithPrefix<OperationAttributes, "gen_ai.operation"> &
    AttributesWithPrefix<TokenAttributes, "gen_ai.token"> &
    AttributesWithPrefix<UsageAttributes, "gen_ai.usage"> &
    AttributesWithPrefix<RequestAttributes, "gen_ai.request"> &
    AttributesWithPrefix<ResponseAttributes, "gen_ai.response">
>;

OperationAttributes interface

Added in v4.0.0 Source

Telemetry attributes which are part of the GenAI specification and are namespaced by gen_ai.operation.

Signature

interface OperationAttributes {
  readonly name?: (string & {}) | WellKnownOperationName | null;
}

RequestAttributes interface

Added in v4.0.0 Source

Telemetry attributes which are part of the GenAI specification and are namespaced by gen_ai.request.

Signature

interface RequestAttributes {
  readonly encodingFormats?: readonly Array<string> | null;
  readonly frequencyPenalty?: number | null;
  readonly maxTokens?: number | null;
  readonly model?: string | null;
  readonly presencePenalty?: number | null;
  readonly seed?: number | null;
  readonly stopSequences?: readonly Array<string> | null;
  readonly temperature?: number | null;
  readonly topK?: number | null;
  readonly topP?: number | null;
}

ResponseAttributes interface

Added in v4.0.0 Source

Telemetry attributes which are part of the GenAI specification and are namespaced by gen_ai.response.

Signature

interface ResponseAttributes {
  readonly finishReasons?: readonly Array<string> | null;
  readonly id?: string | null;
  readonly model?: string | null;
}

SpanTransformer interface

Added in v4.0.0 Source

A function that can transform OpenTelemetry spans based on AI operation data.

Details

Span transformers receive the complete request/response context from AI operations and can add custom telemetry attributes, metrics, or other observability data.

Signature

interface SpanTransformer {
  (options: ProviderOptions & {
    readonly response: readonly Array<AllParts<any>>;
  }): void;
}

TokenAttributes interface

Added in v4.0.0 Source

Telemetry attributes which are part of the GenAI specification and are namespaced by gen_ai.token.

Signature

interface TokenAttributes {
  readonly type?: string | null;
}

UsageAttributes interface

Added in v4.0.0 Source

Telemetry attributes which are part of the GenAI specification and are namespaced by gen_ai.usage.

Signature

interface UsageAttributes {
  readonly inputTokens?: number | null;
  readonly outputTokens?: number | null;
}

WellKnownOperationName type

Added in v4.0.0 Source

The gen_ai.operation.name attribute has the following list of well-known values.

Details

If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Signature

type WellKnownOperationName = "chat" | "embeddings" | "text_completion";

WellKnownSystem type

Added in v4.0.0 Source

The gen_ai.system attribute has the following list of well-known values.

Details

If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Signature

type WellKnownSystem =
  | "anthropic"
  | "aws.bedrock"
  | "az.ai.inference"
  | "az.ai.openai"
  | "cohere"
  | "deepseek"
  | "gemini"
  | "groq"
  | "ibm.watsonx.ai"
  | "mistral_ai"
  | "openai"
  | "perplexity"
  | "vertex_ai"
  | "xai";

Options

GenAITelemetryAttributeOptions type

Added in v4.0.0 Source

Configuration options for GenAI telemetry attributes.

Details

Combines base attributes with optional grouped attributes for comprehensive telemetry coverage of AI operations.

Signature

type GenAITelemetryAttributeOptions = BaseAttributes & {
  readonly operation?: OperationAttributes;
  readonly request?: RequestAttributes;
  readonly response?: ResponseAttributes;
  readonly token?: TokenAttributes;
  readonly usage?: UsageAttributes;
};

Services

CurrentSpanTransformer

Added in v4.0.0 Source

Service tag for providing a SpanTransformer to large language model operations.

When to use

Use to retrieve or provide the current SpanTransformer through context for language model span annotation.

See

Signature

declare class CurrentSpanTransformer extends Shape<
  "effect/ai/Telemetry/CurrentSpanTransformer",
  SpanTransformer,
  this
> {
  constructor(_: never);
}

Utility Types

AttributesWithPrefix type

Added in v4.0.0 Source

Utility type for prefixing attribute names with a namespace.

Details

Transforms attribute keys by adding a prefix and formatting them according to OpenTelemetry conventions (camelCase to snake_case).

Signature

type AttributesWithPrefix<Attributes extends Record<string, any>, Prefix extends string> = {
  [Name in keyof Attributes]: Attributes[Name];
};

FormatAttributeName type

Added in v4.0.0 Source

Utility type for converting camelCase names to snake_case format.

Details

This type recursively transforms string literal types from camelCase to snake_case, which is the standard format for OpenTelemetry attributes.

Signature

type FormatAttributeName<T extends string | number | symbol> = T extends string
  ? T extends `${infer First}${infer Rest}`
    ? `${First extends Uppercase<First> ? "_" : ""}${Lowercase<First>}${FormatAttributeName<Rest>}`
    : T
  : never;