Semantic Conventions for GenAI events

Status: Experimental

GenAI instrumentations MAY capture user inputs sent to the model and responses received from it as events.

Note: Event API is experimental and not yet available in some languages. Check spec-compliance matrix to see the implementation status in corresponding language.

Instrumentations MAY capture inputs and outputs if and only if application has enabled the collection of this data. This is for three primary reasons:

1. Data privacy concerns. End users of GenAI applications may input sensitive information or personally identifiable information (PII) that they do not wish to be sent to a telemetry backend.
2. Data size concerns. Although there is no specified limit to sizes, there are practical limitations in programming languages and telemetry systems. Some GenAI systems allow for extremely large context windows that end users may take full advantage of.
3. Performance concerns. Sending large amounts of data to a telemetry backend may cause performance issues for the application.

Body fields that contain user input, model output, or other potentially sensitive and verbose data SHOULD NOT be captured by default.

Semantic conventions for individual systems which extend content events SHOULD document all additional body fields and specify whether they should be captured by default or need application to opt into capturing them.

Telemetry consumers SHOULD expect to receive unknown body fields.

Instrumentations SHOULD NOT capture undocumented body fields and MUST follow the documented defaults for known fields. Instrumentations MAY offer configuration options allowing to disable events or allowing to capture all fields.

Common attributes

The following attributes apply to all GenAI events.

Attribute	Type	Description	Examples	Requirement Level	Stability
gen_ai.system	string	The Generative AI product as identified by the client or server instrumentation. [1]	openai	Recommended

[1]: The gen_ai.system describes a family of GenAI models with specific model identified by gen_ai.request.model and gen_ai.response.model attributes.

The actual GenAI product may differ from the one identified by the client. For example, when using OpenAI client libraries to communicate with Mistral, the gen_ai.system is set to openai based on the instrumentation’s best knowledge.

For custom model, a custom friendly name SHOULD be used. If none of these options apply, the gen_ai.system SHOULD be set to _OTHER.

gen_ai.system has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
anthropic	Anthropic
cohere	Cohere
openai	OpenAI
vertex_ai	Vertex AI

System event

This event describes the instructions passed to the GenAI model.

The event name MUST be gen_ai.system.message.

User event

This event describes the prompt message specified by the user.

The event name MUST be gen_ai.user.message.

Assistant event

This event describes the assistant message.

The event name MUST be gen_ai.assistant.message.

ToolCall object

Function object

Tool event

This event describes the output of the tool or function submitted back to the model.

The event name MUST be gen_ai.tool.message.

Choice event

This event describes model-generated individual chat response (choice). If GenAI model returns multiple choices, each choice SHOULD be recorded as an individual event.

When response is streamed, instrumentations that report response events MUST reconstruct and report the full message and MUST NOT report individual chunks as events. If the request to GenAI model fails with an error before content is received, instrumentation SHOULD report an event with truncated content (if enabled). If finish_reason was not received, it MUST be set to error.

The event name MUST be gen_ai.choice.

Choice event body has the following fields:

Message object

Custom events

System-specific events that are not covered in this document SHOULD be documented in corresponding Semantic Conventions extensions and SHOULD follow gen_ai.{gen_ai.system}.* naming pattern for system-specific events.

Examples

Chat completion

This example covers the following scenario:

• user requests chat completion from OpenAI GPT-4 model for the following prompt:

  • System message: You're a friendly bot that answers questions about OpenTelemetry.
  • User message: How to instrument GenAI library with OTel?

• The model responds with "Follow GenAI semantic conventions available at opentelemetry.io." message

Span:

Events:

1. gen_ai.system.message.

   Property	Value
   gen_ai.system	"openai"
   Event body	{"content": "You're a friendly bot that answers questions about OpenTelemetry."}

2. gen_ai.user.message

   Property	Value
   gen_ai.system	"openai"
   Event body	{"content":"How to instrument GenAI library with OTel?"}

3. gen_ai.choice

   Property	Value
   gen_ai.system	"openai"
   Event body (with content enabled)	{"index":0,"finish_reason":"stop","message":{"content":"Follow GenAI semantic conventions available at opentelemetry.io."}}
   Event body (without content)	{"index":0,"finish_reason":"stop","message":{}}

Tools

This example covers the following scenario:

1. Application requests chat completion from OpenAI GPT-4 model and provides a function definition.

   • Application provides the following prompt:
     • User message: How to instrument GenAI library with OTel?
   • Application defines a tool (a function) names get_link_to_otel_semconv with single string argument named semconv

2. The model responds with a tool call request which application executes

3. The application requests chat completion again now with the tool execution result

Here’s the telemetry generated for each step in this scenario:

1. Chat completion resulting in a tool call.

   Attribute name	Value
   Span name	"chat gpt-4"
   gen_ai.system	"openai"
   gen_ai.request.model	"gpt-4"
   gen_ai.request.max_tokens	200
   gen_ai.request.top_p	1.0
   gen_ai.response.id	"chatcmpl-9J3uIL87gldCFtiIbyaOvTeYBRA3l"
   gen_ai.response.model	"gpt-4-0613"
   gen_ai.usage.output_tokens	17
   gen_ai.usage.input_tokens	47
   gen_ai.response.finish_reasons	["tool_calls"]

   Events parented to this span:

   • gen_ai.user.message (not reported when capturing content is disabled)

     Property	Value
     gen_ai.system	"openai"
     Event body	{"content":"How to instrument GenAI library with OTel?"}

   • gen_ai.choice

     Property	Value
     gen_ai.system	"openai"
     Event body (with content)	{"index":0,"finish_reason":"tool_calls","message":{"tool_calls":[{"id":"call_VSPygqKTWdrhaFErNvMV18Yl","function":{"name":"get_link_to_otel_semconv","arguments":"{\"semconv\":\"GenAI\"}"},"type":"function"}]}
     Event body (without content)	{"index":0,"finish_reason":"tool_calls","message":{"tool_calls":[{"id":"call_VSPygqKTWdrhaFErNvMV18Yl","function":{"name":"get_link_to_otel_semconv"},"type":"function"}]}

2. Application executes the tool call. Application may create span which is not covered by this semantic convention.

3. Final chat completion call

   Attribute name	Value
   Span name	"chat gpt-4"
   gen_ai.system	"openai"
   gen_ai.request.model	"gpt-4"
   gen_ai.request.max_tokens	200
   gen_ai.request.top_p	1.0
   gen_ai.response.id	"chatcmpl-call_VSPygqKTWdrhaFErNvMV18Yl"
   gen_ai.response.model	"gpt-4-0613"
   gen_ai.usage.output_tokens	52
   gen_ai.usage.input_tokens	47
   gen_ai.response.finish_reasons	["stop"]

   Events parented to this span: (in this example, the event content matches the original messages, but applications may also drop messages or change their content)

   • gen_ai.user.message (not reported when capturing content is not enabled)

     Property	Value
     gen_ai.system	"openai"
     Event body	{"content":"How to instrument GenAI library with OTel?"}

   • gen_ai.assistant.message

     Property	Value
     gen_ai.system	"openai"
     Event body (content enabled)	{"tool_calls":[{"id":"call_VSPygqKTWdrhaFErNvMV18Yl","function":{"name":"get_link_to_otel_semconv","arguments":"{\"semconv\":\"GenAI\"}"},"type":"function"}]}
     Event body (content not enabled)	{"tool_calls":[{"id":"call_VSPygqKTWdrhaFErNvMV18Yl","function":{"name":"get_link_to_otel_semconv"},"type":"function"}]}

   • gen_ai.tool.message

     Property	Value
     gen_ai.system	"openai"
     Event body (content enabled)	{"content":"opentelemetry.io/semconv/gen-ai","id":"call_VSPygqKTWdrhaFErNvMV18Yl"}
     Event body (content not enabled)	{"id":"call_VSPygqKTWdrhaFErNvMV18Yl"}

   • gen_ai.choice

     Property	Value
     gen_ai.system	"openai"
     Event body (content enabled)	{"index":0,"finish_reason":"stop","message":{"content":"Follow OTel semconv available at opentelemetry.io/semconv/gen-ai"}}
     Event body (content not enabled)	{"index":0,"finish_reason":"stop","message":{}}

Chat completion with multiple choices

This example covers the following scenario:

• user requests 2 chat completion from OpenAI GPT-4 model for the following prompt:

  • System message: You're a friendly bot that answers questions about OpenTelemetry.
  • User message: How to instrument GenAI library with OTel?

• The model responds with two choices

  • "Follow GenAI semantic conventions available at opentelemetry.io." message
  • "Use OpenAI instrumentation library." message

Span:

Events:

1. gen_ai.system.message: the same as in the Chat Completion example

2. gen_ai.user.message: the same as in the previous example

3. gen_ai.choice

   Property	Value
   gen_ai.system	"openai"
   Event body (content enabled)	{"index":0,"finish_reason":"stop","message":{"content":"Follow GenAI semantic conventions available at opentelemetry.io."}}

4. gen_ai.choice

   Property	Value
   gen_ai.system	"openai"
   Event body (content enabled)	{"index":1,"finish_reason":"stop","message":{"content":"Use OpenAI instrumentation library."}}